如何使用纯 Javascript 使 HTML 元素可调整大小？
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【中文标题】如何使用纯 Javascript 使 HTML 元素可调整大小？【英文标题】：How to make HTML element resizable using pure Javascript? 【发布时间】：2012-02-16 03:03:12 【问题描述】：我想知道如何使用纯 javascript（而不是 jQuery 库或任何其他库）单击 html 元素，如 <div> 或 <p> 标记元素。
【问题讨论】：
“可调整大小”是什么意思？如果你想调整窗口大小，你可以设置元素的宽度，单位为 %。 这是我调整 div 元素大小的方法：***.com/questions/43411103/… 高度相关：***.com/questions/12194469/… 【参考方案1】：我真的建议使用某种库，但你要求它，你得到它：
var p = document.querySelector('p'); // element to make resizable
p.addEventListener('click', function init()
p.removeEventListener('click', init, false);
p.className = p.className + ' resizable';
var resizer = document.createElement('div');
resizer.className = 'resizer';
p.appendChild(resizer);
resizer.addEventListener('mousedown', initDrag, false);
, false);
var startX, startY, startWidth, startHeight;
function initDrag(e)
startX = e.clientX;
startY = e.clientY;
startWidth = parseInt(document.defaultView.getComputedStyle(p).width, 10);
startHeight = parseInt(document.defaultView.getComputedStyle(p).height, 10);
document.documentElement.addEventListener('mousemove', doDrag, false);
document.documentElement.addEventListener('mouseup', stopDrag, false);
function doDrag(e)
p.style.width = (startWidth + e.clientX - startX) + 'px';
p.style.height = (startHeight + e.clientY - startY) + 'px';
function stopDrag(e)
document.documentElement.removeEventListener('mousemove', doDrag, false);
document.documentElement.removeEventListener('mouseup', stopDrag, false);
Demo
请记住，这可能无法在所有浏览器中运行（仅在 Firefox 中测试，绝对不能在 IE
【讨论】：
一个问题，'10'这个值在代码中是做什么的 parseInt(document.defaultView.getComputedStyle(p).width, 10); 我在脚本中发现了一个错误，如果您尝试在有多个 p 标签元素时使多个 p 标签元素可调整大小，那么代码不起作用，有什么解决方案吗？ 您实际上不会在生产中使用它，是吗？上面的代码显然是一个快速破解，还有其他几个问题。这只是为了展示事情在低层次上是如何运作的。 +1 我知道它是低级的，但是当您出于任何原因无法使用 3rd 方库时它非常有用。我已经在 Chrome、Firefox、Opera 和 Safari 上测试过了。 我修复了 jsfiddle。这应该可以工作并达到相同的效果。 jsfiddle.net/MissoulaLorenzo/gfn6ob3j【参考方案2】：纯 css3 解决方案怎么样？
div
resize: both;
overflow: auto;
MDN Web Docs
W3Schools example
Browser support
【讨论】：
很遗憾，IE 不支持 CSS 调整大小 我认为重要的是要提到：使用 cssresize Webkit 浏览器不会让您调整元素的大小以使其更小，只能更大（在两个维度上）。
我在 Chrome 53 中尝试过，它适用于收缩和拉伸。
很高兴知道这一点。但我需要一个可调整大小的页脚，可以调整到顶部。 “调整大小”似乎不可能。
谢谢你救了我！我需要使 iframe 可调整大小并且它可以工作。 javascript 中的任何内容都不适用于 iframe。【参考方案3】：
很简单：
例如：https://jsfiddle.net/RainStudios/mw786v1w/
var element = document.getElementById('element');
//create box in bottom-left
var resizer = document.createElement('div');
resizer.style.width = '10px';
resizer.style.height = '10px';
resizer.style.background = 'red';
resizer.style.position = 'absolute';
resizer.style.right = 0;
resizer.style.bottom = 0;
resizer.style.cursor = 'se-resize';
//Append Child to Element
element.appendChild(resizer);
//box function onmousemove
resizer.addEventListener('mousedown', initResize, false);
//Window funtion mousemove & mouseup
function initResize(e)
window.addEventListener('mousemove', Resize, false);
window.addEventListener('mouseup', stopResize, false);
//resize the element
function Resize(e)
element.style.width = (e.clientX - element.offsetLeft) + 'px';
element.style.height = (e.clientY - element.offsetTop) + 'px';
//on mouseup remove windows functions mousemove & mouseup
function stopResize(e)
window.removeEventListener('mousemove', Resize, false);
window.removeEventListener('mouseup', stopResize, false);
【讨论】：
很好的解决方案！经过测试并适用于 Firefox56、Chrome61、Opera48 和 IE11。 这很好用！我一直在寻找解决这个问题的起点，这给了我一些工作。【参考方案4】：查看我的跨浏览器兼容resizer。
<!doctype html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>resizer</title>
<meta name="author" content="Andrej Hristoliubov anhr@mail.ru">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript" src="https://rawgit.com/anhr/resizer/master/Common.js"></script>
<script type="text/javascript" src="https://rawgit.com/anhr/resizer/master/resizer.js"></script>
<style>
.element
border: 1px solid #999999;
border-radius: 4px;
margin: 5px;
padding: 5px;
</style>
<script type="text/javascript">
function onresize()
var element1 = document.getElementById("element1");
var element2 = document.getElementById("element2");
var element3 = document.getElementById("element3");
var ResizerY = document.getElementById("resizerY");
ResizerY.style.top = element3.offsetTop - 15 + "px";
var topElements = document.getElementById("topElements");
topElements.style.height = ResizerY.offsetTop - 20 + "px";
var height = topElements.clientHeight - 32;
if (height < 0)
height = 0;
height += 'px';
element1.style.height = height;
element2.style.height = height;
function resizeX(x)
//consoleLog("mousemove(X = " + e.pageX + ")");
var element2 = document.getElementById("element2");
element2.style.width =
element2.parentElement.clientWidth
+ document.getElementById('rezizeArea').offsetLeft
- x
+ 'px';
function resizeY(y)
//consoleLog("mousemove(Y = " + e.pageY + ")");
var element3 = document.getElementById("element3");
var height =
element3.parentElement.clientHeight
+ document.getElementById('rezizeArea').offsetTop
- y
;
//consoleLog("mousemove(Y = " + e.pageY + ") height = " + height + " element3.parentElement.clientHeight = " + element3.parentElement.clientHeight);
if ((height + 100) > element3.parentElement.clientHeight)
return;//Limit of the height of the elemtnt 3
element3.style.height = height + 'px';
onresize();
var emailSubject = "Resizer example error";
</script>
</head>
<body>
<div id='Message'></div>
<h1>Resizer</h1>
<p>Please see example of resizing of the HTML element by mouse dragging.</p>
<ul>
<li>Drag the red rectangle if you want to change the width of the Element 1 and Element 2</li>
<li>Drag the green rectangle if you want to change the height of the Element 1 Element 2 and Element 3</li>
<li>Drag the small blue square at the left bottom of the Element 2, if you want to resize of the Element 1 Element 2 and Element 3</li>
</ul>
<div id="rezizeArea" style="width:1000px; height:250px; overflow:auto; position: relative;" class="element">
<div id="topElements" class="element" style="overflow:auto; position:absolute; left: 0; top: 0; right:0;">
<div id="element2" class="element" style="width: 30%; height:10px; float: right; position: relative;">
Element 2
<div id="resizerXY" style="width: 10px; height: 10px; background: blue; position:absolute; left: 0; bottom: 0;"></div>
<script type="text/javascript">
resizerXY("resizerXY", function (e)
resizeX(e.pageX + 10);
resizeY(e.pageY + 50);
);
</script>
</div>
<div id="resizerX" style="width: 10px; height:100%; background: red; float: right;"></div>
<script type="text/javascript">
resizerX("resizerX", function (e)
resizeX(e.pageX + 25);
);
</script>
<div id="element1" class="element" style="height:10px; overflow:auto;">Element 1</div>
</div>
<div id="resizerY" style="height:10px; position:absolute; left: 0; right:0; background: green;"></div>
<script type="text/javascript">
resizerY("resizerY", function (e)
resizeY(e.pageY + 25);
);
</script>
<div id="element3" class="element" style="height:100px; position:absolute; left: 0; bottom: 0; right:0;">Element 3</div>
</div>
<script type="text/javascript">
onresize();
</script>
</body>
</html>另请参阅我的 resizer 示例
【讨论】：
值得注意的是，当我在 Firefox（在 Linux 上）中尝试您的示例时，水平和垂直调整大小会导致文本在选中和未选中之间来回闪烁。【参考方案5】：只需在原版 js 中使用 mousemove 事件
步骤
将mousemove 添加到您的目标
监听目标move事件
获取指针位置，调整目标大小
代码
const div = document.querySelector(`div.before`);
const box = document.querySelector(`div.container`);
box.addEventListener(`mousemove`, (e) =>
const
offsetX,
offsetY,
= e;
div.style.width = offsetX + `px`;
);
现场演示
https://codepen.io/xgqfrms/full/wvMQqZL
参考
https://developer.mozilla.org/en-US/docs/Web/API/Element/mousemove_event
https://medium.com/the-z/making-a-resizable-div-in-js-is-not-easy-as-you-think-bda19a1bc53d
【讨论】：
【参考方案6】：我刚刚创建了一个 CodePen，它展示了如何使用 ES6 轻松完成。
http://codepen.io/travist/pen/GWRBQV
基本上，这是执行此操作的类。
let getPropertyValue = function(style, prop)
let value = style.getPropertyValue(prop);
value = value ? value.replace(/[^0-9.]/g, '') : '0';
return parseFloat(value);
let getElementRect = function(element)
let style = window.getComputedStyle(element, null);
return
x: getPropertyValue(style, 'left'),
y: getPropertyValue(style, 'top'),
width: getPropertyValue(style, 'width'),
height: getPropertyValue(style, 'height')
class Resizer
constructor(wrapper, element, options)
this.wrapper = wrapper;
this.element = element;
this.options = options;
this.offsetX = 0;
this.offsetY = 0;
this.handle = document.createElement('div');
this.handle.setAttribute('class', 'drag-resize-handlers');
this.handle.setAttribute('data-direction', 'br');
this.wrapper.appendChild(this.handle);
this.wrapper.style.top = this.element.style.top;
this.wrapper.style.left = this.element.style.left;
this.wrapper.style.width = this.element.style.width;
this.wrapper.style.height = this.element.style.height;
this.element.style.position = 'relative';
this.element.style.top = 0;
this.element.style.left = 0;
this.onResize = this.resizeHandler.bind(this);
this.onStop = this.stopResize.bind(this);
this.handle.addEventListener('mousedown', this.initResize.bind(this));
initResize(event)
this.stopResize(event, true);
this.handle.addEventListener('mousemove', this.onResize);
this.handle.addEventListener('mouseup', this.onStop);
resizeHandler(event)
this.offsetX = event.clientX - (this.wrapper.offsetLeft + this.handle.offsetLeft);
this.offsetY = event.clientY - (this.wrapper.offsetTop + this.handle.offsetTop);
let wrapperRect = getElementRect(this.wrapper);
let elementRect = getElementRect(this.element);
this.wrapper.style.width = (wrapperRect.width + this.offsetX) + 'px';
this.wrapper.style.height = (wrapperRect.height + this.offsetY) + 'px';
this.element.style.width = (elementRect.width + this.offsetX) + 'px';
this.element.style.height = (elementRect.height + this.offsetY) + 'px';
stopResize(event, nocb)
this.handle.removeEventListener('mousemove', this.onResize);
this.handle.removeEventListener('mouseup', this.onStop);
class Dragger
constructor(wrapper, element, options)
this.wrapper = wrapper;
this.options = options;
this.element = element;
this.element.draggable = true;
this.element.setAttribute('draggable', true);
this.element.addEventListener('dragstart', this.dragStart.bind(this));
dragStart(event)
let wrapperRect = getElementRect(this.wrapper);
var x = wrapperRect.x - parseFloat(event.clientX);
var y = wrapperRect.y - parseFloat(event.clientY);
event.dataTransfer.setData("text/plain", this.element.id + ',' + x + ',' + y);
dragStop(event, prevX, prevY)
var posX = parseFloat(event.clientX) + prevX;
var posY = parseFloat(event.clientY) + prevY;
this.wrapper.style.left = posX + 'px';
this.wrapper.style.top = posY + 'px';
class DragResize
constructor(element, options)
options = options || ;
this.wrapper = document.createElement('div');
this.wrapper.setAttribute('class', 'tooltip drag-resize');
if (element.parentNode)
element.parentNode.insertBefore(this.wrapper, element);
this.wrapper.appendChild(element);
element.resizer = new Resizer(this.wrapper, element, options);
element.dragger = new Dragger(this.wrapper, element, options);
document.body.addEventListener('dragover', function (event)
event.preventDefault();
return false;
);
document.body.addEventListener('drop', function (event)
event.preventDefault();
var dropData = event.dataTransfer.getData("text/plain").split(',');
var element = document.getElementById(dropData[0]);
element.dragger.dragStop(event, parseFloat(dropData[1]), parseFloat(dropData[2]));
return false;
);
【讨论】：
“很容易”：大声笑 - 另外，这对我来说很糟糕；似乎在选择和取消选择文本时遇到问题。【参考方案7】：我创建了一个函数，它接收一个 html 元素的 id 并在它的右侧添加一个边框 该函数是通用的，只接收一个 id，因此您可以按原样复制它，它会起作用
var myoffset;
function resizeE(elem)
var borderDiv = document.createElement("div");
borderDiv.className = "border";
borderDiv.addEventListener("mousedown",myresize = function myrsize(e)
myoffset = e.clientX - (document.getElementById(elem).offsetLeft + parseInt(window.getComputedStyle(document.getElementById(elem)).getPropertyValue("width")));
window.addEventListener("mouseup",mouseUp);
document.addEventListener("mousemove",mouseMove = function mousMove(e)
document.getElementById(elem).style.width = `$e.clientX - myoffset - document.getElementById(elem).offsetLeftpx`;
);
);
document.getElementById(elem).appendChild(borderDiv);
function mouseUp()
document.removeEventListener("mousemove", mouseMove);
window.removeEventListener("mouseup",mouseUp);
function load()
resizeE("resizeableDiv");
resizeE("anotherresizeableDiv");
resizeE("anotherresizeableDiv1");
.border
position: absolute;
cursor: e-resize;
width: 9px;
right: -5px;
top: 0;
height: 100%;
#resizeableDiv
width: 30vw;
height: 30vh;
background-color: #84f4c6;
position: relative;
#anotherresizeableDiv
width: 30vw;
height: 30vh;
background-color: #9394f4;
position: relative;
#anotherresizeableDiv1
width: 30vw;
height: 30vh;
background-color: #43f4f4;
position: relative;
#anotherresizeableDiv1 .border
background-color: black;
#anotherresizeableDiv .border
width: 30px;
right: -200px;
background-color: green;
<body onload="load()">
<div id="resizeableDiv">change my size with the east border</div>
<div id="anotherresizeableDiv1">with visible border</div>
</body>
<div id="anotherresizeableDiv">with editted outside border</div>
</body>resizeE("resizeableDiv"); //this calls a function that does the magic to the id inserted
【讨论】：
【参考方案8】：这里有很好的例子可以开始尝试，但都是基于添加一些额外的或外部的元素，如“div”作为参考元素来拖动它，并计算原始的新尺寸或位置元素。
这是一个不使用任何额外元素的示例。我们可以在不影响其操作的情况下添加边框、填充或边距。 在此示例中，我们没有添加颜色，也没有添加任何对边框或右下角的视觉参考作为您可以放大或缩小尺寸的线索，但是使用光标围绕可调整大小的元素会出现线索！
let resizerForCenter = new Resizer('center')
resizerForCenter.initResizer()
用 CodeSandbox 来看看它的实际效果：
在这个示例中，我们使用 ES6，以及一个导出名为 Resizer 的类的模块。 一个例子值一千字：
或者用代码sn-p：
const html = document.querySelector('html')
class Resizer
constructor(elemId)
this._elem = document.getElementById(elemId)
/**
* Stored binded context handlers for method passed to eventListeners!
*
* See: https://***.com/questions/9720927/removing-event-listeners-as-class-prototype-functions
*/
this._checkBorderHandler = this._checkBorder.bind(this)
this._doResizeHandler = this._doResize.bind(this)
this._initResizerHandler = this.initResizer.bind(this)
this._onResizeHandler = this._onResize.bind(this)
initResizer()
this.stopResizer()
this._beginResizer()
_beginResizer()
this._elem.addEventListener('mousemove', this._checkBorderHandler, false)
stopResizer()
html.style.cursor = 'default'
this._elem.style.cursor = 'default'
window.removeEventListener('mousemove', this._doResizeHandler, false)
window.removeEventListener('mouseup', this._initResizerHandler, false)
this._elem.removeEventListener('mousedown', this._onResizeHandler, false)
this._elem.removeEventListener('mousemove', this._checkBorderHandler, false)
_doResize(e)
let elem = this._elem
let boxSizing = getComputedStyle(elem).boxSizing
let borderRight = 0
let borderLeft = 0
let borderTop = 0
let borderBottom = 0
let paddingRight = 0
let paddingLeft = 0
let paddingTop = 0
let paddingBottom = 0
switch (boxSizing)
case 'content-box':
paddingRight = parseInt(getComputedStyle(elem).paddingRight)
paddingLeft = parseInt(getComputedStyle(elem).paddingLeft)
paddingTop = parseInt(getComputedStyle(elem).paddingTop)
paddingBottom = parseInt(getComputedStyle(elem).paddingBottom)
break
case 'border-box':
borderRight = parseInt(getComputedStyle(elem).borderRight)
borderLeft = parseInt(getComputedStyle(elem).borderLeft)
borderTop = parseInt(getComputedStyle(elem).borderTop)
borderBottom = parseInt(getComputedStyle(elem).borderBottom)
break
default: break
let horizontalAdjustment = (paddingRight + paddingLeft) - (borderRight + borderLeft)
let verticalAdjustment = (paddingTop + paddingBottom) - (borderTop + borderBottom)
let newWidth = elem.clientWidth + e.movementX - horizontalAdjustment + 'px'
let newHeight = elem.clientHeight + e.movementY - verticalAdjustment + 'px'
let cursorType = getComputedStyle(elem).cursor
switch (cursorType)
case 'all-scroll':
elem.style.width = newWidth
elem.style.height = newHeight
break
case 'col-resize':
elem.style.width = newWidth
break
case 'row-resize':
elem.style.height = newHeight
break
default: break
_onResize(e)
// On resizing state!
let elem = e.target
let newCursorType = undefined
let cursorType = getComputedStyle(elem).cursor
switch (cursorType)
case 'nwse-resize':
newCursorType = 'all-scroll'
break
case 'ew-resize':
newCursorType = 'col-resize'
break
case 'ns-resize':
newCursorType = 'row-resize'
break
default: break
html.style.cursor = newCursorType // Avoid cursor's flickering
elem.style.cursor = newCursorType
// Remove what is not necessary, and could have side effects!
elem.removeEventListener('mousemove', this._checkBorderHandler, false);
// Events on resizing state
/**
* We do not apply the mousemove event on the elem to resize it, but to the window to prevent the mousemove from slippe out of the elem to resize. This work bc we calculate things based on the mouse position
*/
window.addEventListener('mousemove', this._doResizeHandler, false);
window.addEventListener('mouseup', this._initResizerHandler, false);
_checkBorder(e)
const elem = e.target
const borderSensitivity = 5
const coor = getCoordenatesCursor(e)
const onRightBorder = ((coor.x + borderSensitivity) > elem.scrollWidth)
const onBottomBorder = ((coor.y + borderSensitivity) > elem.scrollHeight)
const onBottomRightCorner = (onRightBorder && onBottomBorder)
if (onBottomRightCorner)
elem.style.cursor = 'nwse-resize'
else if (onRightBorder)
elem.style.cursor = 'ew-resize'
else if (onBottomBorder)
elem.style.cursor = 'ns-resize'
else
elem.style.cursor = 'auto'
if (onRightBorder || onBottomBorder)
elem.addEventListener('mousedown', this._onResizeHandler, false)
else
elem.removeEventListener('mousedown', this._onResizeHandler, false)
function getCoordenatesCursor(e)
let elem = e.target;
// Get the Viewport-relative coordinates of cursor.
let viewportX = e.clientX
let viewportY = e.clientY
// Viewport-relative position of the target element.
let elemRectangle = elem.getBoundingClientRect()
// The function returns the largest integer less than or equal to a given number.
let x = Math.floor(viewportX - elemRectangle.left) // - elem.scrollWidth
let y = Math.floor(viewportY - elemRectangle.top) // - elem.scrollHeight
return x, y
let resizerForCenter = new Resizer('center')
resizerForCenter.initResizer()
let resizerForLeft = new Resizer('left')
resizerForLeft.initResizer()
setTimeout(handler, 10000, true); // 10s
function handler()
resizerForCenter.stopResizer()
body
background-color: white;
#wrapper div
/* box-sizing: border-box; */
position: relative;
float:left;
overflow: hidden;
height: 50px;
width: 50px;
padding: 3px;
#left
background-color: blueviolet;
#center
background-color:lawngreen ;
#right
background: blueviolet;
#wrapper
border: 5px solid hotpink;
display: inline-block;
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Resizer v0.0.1</title>
</head>
<body>
<div id="wrapper">
<div id="left">Left</div>
<div id="center">Center</div>
<div id="right">Right</div>
</div>
</body>
</html>【讨论】：
【参考方案9】：// import
function get_difference(pre, mou)
return
x: mou.x - pre.x,
y: mou.y - pre.y
;
/*
if your panel is in a nested environment, which the parent container's width and height does not equa to document width
and height, for example, in an element `canvas`, then edit it to
function oMousePos(e)
var rc = canvas.getBoundingClientRect();
return
x: e.clientX - rc.left,
y: e.clientY - rc.top,
;
*/
function oMousePos(e)
return
x: e.clientX,
y: e.clientY,
;
function render_element(styles, el)
for (const [kk, vv] of Object.entries(styles))
el.style[kk] = vv;
class MoveablePanel
/*
prevent an element from moving out of window
*/
constructor(container, draggable, left, top)
this.container = container;
this.draggable = draggable;
this.left = left;
this.top = top;
let rect = container.getBoundingClientRect();
this.width = rect.width;
this.height = rect.height;
this.status = false;
// initial position of the panel, should not be changed
this.original =
left: left,
top: top
;
// current left and top postion
// this.left, this.top
// assign the panel to initial position
// initalize in registration
this.default();
if (!MoveablePanel._instance)
MoveablePanel._instance = [];
MoveablePanel._instance.push(this);
mousedown(e)
this.status = true;
this.previous = oMousePos(e)
mousemove(e)
if (!this.status)
return;
let pos = oMousePos(e);
let vleft = this.left + pos.x - this.previous.x;
let vtop = this.top + pos.y - this.previous.y;
let kleft, ktop;
if (vleft < 0)
kleft = 0;
else if (vleft > window.innerWidth - this.width)
kleft = window.innerWidth - this.width;
else
kleft = vleft;
if (vtop < 0)
ktop = 0;
else if (vtop > window.innerHeight - this.height)
ktop = window.innerHeight - this.height;
else
ktop = vtop;
this.container.style.left = `$kleftpx`;
this.container.style.top = `$ktoppx`;
/*
sometimes user move the cursor too fast which mouseleave is previous than mouseup
to prevent moving too fast and break the control, mouseleave is handled the same as mouseup
*/
mouseupleave(e)
if (!this.status)
return null;
this.status = false;
let pos = oMousePos(e);
let vleft = this.left + pos.x - this.previous.x;
let vtop = this.top + pos.y - this.previous.y;
if (vleft < 0)
this.left = 0;
else if (vleft > window.innerWidth - this.width)
this.left = window.innerWidth - this.width;
else
this.left = vleft;
if (vtop < 0)
this.top = 0;
else if (vtop > window.innerHeight - this.height)
this.top = window.innerHeight - this.height;
else
this.top = vtop;
this.show();
return true;
default ()
this.container.style.left = `$this.original.leftpx`;
this.container.style.top = `$this.original.toppx`;
/*
panel with a higher z index will interupt drawing
therefore if panel is not displaying, set it with a lower z index that canvas
change index doesn't work, if panel is hiding, then we move it out
hide: record current position, move panel out
show: assign to recorded position
notice this position has nothing to do panel drag movement
they cannot share the same variable
*/
hide()
// move to the right bottom conner
this.container.style.left = `$window.screen.widthpx`;
this.container.style.top = `$window.screen.heightpx`;
show()
this.container.style.left = `$this.leftpx`;
this.container.style.top = `$this.toppx`;
// end of import
class DotButton
constructor(
width_px,
styles, // mainly pos, padding and margin, e.g. top: 0, left: 0, margin: 0,
color,
color_hover,
border, // boolean
border_dismiss, // boolean: dismiss border when hover
)
this.width = width_px;
this.styles = styles;
this.color = color;
this.color_hover = color_hover;
this.border = border;
this.border_dismiss = border_dismiss;
create(_styles=null)
var el = document.createElement('div');
Object.keys(this.styles).forEach(kk=>
el.style[kk] = `$this.styles[kk]px`;
);
if(_styles)
Object.keys(_styles).forEach(kk=>
el.style[kk] = `$this.styles[kk]px`;
);
el.style.width = `$this.widthpx`
el.style.height = `$this.widthpx`
el.style.position = 'absolute';
el.style.left = `$this.left_pxpx`;
el.style.top = `$this.top_pxpx`;
el.style.background = this.color;
if(this.border)
el.style.border = '1px solid';
el.style.borderRadius = `$this.widthpx`;
el.addEventListener('mouseenter', ()=>
el.style.background = this.color_hover;
if(this.border_dismiss)
el.style.border = `1px solid $this.color_hover`;
);
el.addEventListener('mouseleave', ()=>
el.style.background = this.color;
if(this.border_dismiss)
el.style.border = '1px solid';
);
return el;
function cursor_hover(el, default_cursor, to_cursor)
el.addEventListener('mouseenter', function()
this.style.cursor = to_cursor;
.bind(el));
el.addEventListener('mouseleave', function()
this.style.cursor = default_cursor;
.bind(el));
class FlexPanel extends MoveablePanel
constructor(
parent_el,
top_px,
left_px,
width_px,
height_px,
background,
handle_width_px,
coner_vmin_ratio,
button_width_px,
button_margin_px,
)
super(
(()=>
var el = document.createElement('div');
render_element(
position: 'fixed',
top: `$top_pxpx`,
left: `$left_pxpx`,
width: `$width_pxpx`,
height: `$height_pxpx`,
background: background,
,
el,
);
return el;
)(), // iife returns a container (panel el)
new DotButton(button_width_px, top: 0, right: 0, margin: button_margin_px, 'green', 'lightgreen', false, false).create(), // draggable
left_px, // left
top_px, // top
);
this.draggable.addEventListener('mousedown', e =>
e.preventDefault();
this.mousedown(e);
);
this.draggable.addEventListener('mousemove', e =>
e.preventDefault();
this.mousemove(e);
);
this.draggable.addEventListener('mouseup', e =>
e.preventDefault();
this.mouseupleave(e);
);
this.draggable.addEventListener('mouseleave', e =>
e.preventDefault();
this.mouseupleave(e);
);
this.parent_el = parent_el;
this.background = background;
// parent
this.width = width_px;
this.height = height_px;
this.handle_width_px = handle_width_px;
this.coner_vmin_ratio = coner_vmin_ratio;
this.panel_el = document.createElement('div');
// styles that won't change
this.panel_el.style.position = 'absolute';
this.panel_el.style.top = `$this.handle_width_pxpx`;
this.panel_el.style.left = `$this.handle_width_pxpx`;
this.panel_el.style.background = this.background;
this.handles = [
this.handle_top,
this.handle_left,
this.handle_bottom,
this.handle_right,
this.handle_lefttop,
this.handle_topleft,
this.handle_topright,
this.handle_righttop,
this.handle_rightbottom,
this.handle_bottomright,
this.handle_bottomleft,
this.handle_leftbottom,
] = Array.from(length: 12, i => document.createElement('div'));
this.handles.forEach(el=>
el.style.position = 'absolute';
);
this.handle_topleft.style.top = '0';
this.handle_topleft.style.left = `$this.handle_width_pxpx`;
this.handle_righttop.style.right = '0';
this.handle_righttop.style.top = `$this.handle_width_pxpx`;
this.handle_bottomright.style.bottom = '0';
this.handle_bottomright.style.right = `$this.handle_width_pxpx`;
this.handle_leftbottom.style.left = '0';
this.handle_leftbottom.style.bottom = `$this.handle_width_pxpx`;
this.handle_lefttop.style.left = '0';
this.handle_lefttop.style.top = '0';
this.handle_topright.style.top = '0';
this.handle_topright.style.right = '0';
this.handle_rightbottom.style.right = '0';
this.handle_rightbottom.style.bottom = '0';
this.handle_bottomleft.style.bottom = '0';
this.handle_bottomleft.style.left = '0';
this.update_ratio();
[
'ns-resize', // |
'ew-resize', // -
'ns-resize', // |
'ew-resize', // -
'nwse-resize', // \
'nwse-resize', // \
'nesw-resize', // /
'nesw-resize', // /
'nwse-resize', // \
'nwse-resize', // \
'nesw-resize', // /
'nesw-resize', // /
].map((dd, ii)=>
cursor_hover(this.handles[ii], 'default', dd);
);
this.vtop = this.top;
this.vleft = this.left;
this.vwidth = this.width;
this.vheight = this.height;
this.update_ratio();
this.handles.forEach(el=>
this.container.appendChild(el);
);
cursor_hover(this.draggable, 'default', 'move');
this.panel_el.appendChild(this.draggable);
this.container.appendChild(this.panel_el);
this.parent_el.appendChild(this.container);
[
this.edgemousedown,
this.verticalmousemove,
this.horizontalmousemove,
this.nwsemousemove,
this.neswmousemove,
this.edgemouseupleave,
] = [
this.edgemousedown.bind(this),
this.verticalmousemove.bind(this),
this.horizontalmousemove.bind(this),
this.nwsemousemove.bind(this),
this.neswmousemove.bind(this),
this.edgemouseupleave.bind(this),
];
this.handle_top.addEventListener('mousedown', e=>this.edgemousedown(e, 'top'));
this.handle_left.addEventListener('mousedown', e=>this.edgemousedown(e, 'left'));
this.handle_bottom.addEventListener('mousedown', e=>this.edgemousedown(e, 'bottom'));
this.handle_right.addEventListener('mousedown', e=>this.edgemousedown(e, 'right'));
this.handle_lefttop.addEventListener('mousedown', e=>this.edgemousedown(e, 'lefttop'));
this.handle_topleft.addEventListener('mousedown', e=>this.edgemousedown(e, 'topleft'));
this.handle_topright.addEventListener('mousedown', e=>this.edgemousedown(e, 'topright'));
this.handle_righttop.addEventListener('mousedown', e=>this.edgemousedown(e, 'righttop'));
this.handle_rightbottom.addEventListener('mousedown', e=>this.edgemousedown(e, 'rightbottom'));
this.handle_bottomright.addEventListener('mousedown', e=>this.edgemousedown(e, 'bottomright'));
this.handle_bottomleft.addEventListener('mousedown', e=>this.edgemousedown(e, 'bottomleft'));
this.handle_leftbottom.addEventListener('mousedown', e=>this.edgemousedown(e, 'leftbottom'));
this.handle_top.addEventListener('mousemove', this.verticalmousemove);
this.handle_left.addEventListener('mousemove', this.horizontalmousemove);
this.handle_bottom.addEventListener('mousemove', this.verticalmousemove);
this.handle_right.addEventListener('mousemove', this.horizontalmousemove);
this.handle_lefttop.addEventListener('mousemove', this.nwsemousemove);
this.handle_topleft.addEventListener('mousemove', this.nwsemousemove);
this.handle_topright.addEventListener('mousemove', this.neswmousemove);
this.handle_righttop.addEventListener('mousemove', this.neswmousemove);
this.handle_rightbottom.addEventListener('mousemove', this.nwsemousemove);
this.handle_bottomright.addEventListener('mousemove', this.nwsemousemove);
this.handle_bottomleft.addEventListener('mousemove', this.neswmousemove);
this.handle_leftbottom.addEventListener('mousemove', this.neswmousemove);
this.handle_top.addEventListener('mouseup', e=>this.verticalmousemove(e); this.edgemouseupleave());
this.handle_left.addEventListener('mouseup', e=>this.horizontalmousemove(e); this.edgemouseupleave());
this.handle_bottom.addEventListener('mouseup', e=>this.verticalmousemove(e); this.edgemouseupleave());
this.handle_right.addEventListener('mouseup', e=>this.horizontalmousemove(e); this.edgemouseupleave());
this.handle_lefttop.addEventListener('mouseup', e=>this.nwsemousemove(e); this.edgemouseupleave());
this.handle_topleft.addEventListener('mouseup', e=>this.nwsemousemove(e); this.edgemouseupleave());
this.handle_topright.addEventListener('mouseup', e=>this.neswmousemove(e); this.edgemouseupleave());
this.handle_righttop.addEventListener('mouseup', e=>this.neswmousemove(e); this.edgemouseupleave());
this.handle_rightbottom.addEventListener('mouseup', e=>this.nwsemousemove(e); this.edgemouseupleave());
this.handle_bottomright.addEventListener('mouseup', e=>this.nwsemousemove(e); this.edgemouseupleave());
this.handle_bottomleft.addEventListener('mouseup', e=>this.neswmousemove(e); this.edgemouseupleave());
this.handle_leftbottom.addEventListener('mouseup', e=>this.neswmousemove(e); this.edgemouseupleave());
this.handle_top.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_left.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_bottom.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_right.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_lefttop.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_topleft.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_topright.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_righttop.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_rightbottom.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_bottomright.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_bottomleft.addEventListener('mouseleave', this.edgemouseupleave);
this.handle_leftbottom.addEventListener('mouseleave', this.edgemouseupleave);
// box size change triggers corner handler size change
update_ratio()
this.container.style.top = `$this.vtoppx`;
this.container.style.left = `$this.vleftpx`;
this.container.style.width = `$this.vwidthpx`;
this.container.style.height = `$this.vheightpx`;
this.panel_el.style.width = `$this.vwidth - 2 * this.handle_width_pxpx`;
this.panel_el.style.height = `$this.vheight - 2 * this.handle_width_pxpx`;
this.ratio = this.vwidth < this.vheight ? this.coner_vmin_ratio * this.vwidth : this.coner_vmin_ratio * this.vheight;
[
this.handle_top,
this.handle_bottom,
].forEach(el=>
el.style.width = `$this.vwidth - 2 * this.ratiopx`;
el.style.height = `$this.handle_width_pxpx`;
);
[
this.handle_left,
this.handle_right,
].forEach(el=>
el.style.height = `$this.vheight - 2 * this.ratiopx`;
el.style.width = `$this.handle_width_pxpx`;
);
this.handle_top.style.top = `0`;
this.handle_top.style.left = `$this.ratiopx`;
this.handle_left.style.top = `$this.ratiopx`;
this.handle_left.style.left = `0`;
this.handle_bottom.style.bottom = `0`;
this.handle_bottom.style.right = `$this.ratiopx`;
this.handle_right.style.bottom = `$this.ratiopx`;
this.handle_right.style.right = `0`;
[
this.handle_topright,
this.handle_bottomleft,
].forEach(el=>
el.style.width = `$this.ratiopx`;
el.style.height = `$this.handle_width_pxpx`;
);
[
this.handle_lefttop,
this.handle_rightbottom,
].forEach(el=>
el.style.width = `$this.handle_width_pxpx`;
el.style.height = `$this.ratiopx`;
);
[
this.handle_topleft,
this.handle_bottomright,
].forEach(el=>
el.style.width = `$this.ratio - this.handle_width_pxpx`;
el.style.height = `$this.handle_width_pxpx`;
);
[
this.handle_righttop,
this.handle_leftbottom,
].forEach(el=>
el.style.height = `$this.handle_width_pxpx`;
el.style.width = `$this.ratio - this.handle_width_pxpx`;
);
edgemousedown(e, flag)
this.previous = oMousePos(e);
this.flag = flag;
this.drag = true;
verticalmousemove(e)
if(this.drag)
// -
this.mouse = oMousePos(e);
var ydif = this.mouse.y - this.previous.y;
switch(this.flag)
case 'top':
this.vtop = this.top + ydif;
this.vheight = this.height - ydif;
this.vleft = this.left;
this.vwidth = this.width;
break;
case 'bottom':
this.vheight = this.height + ydif;
this.vtop = this.top;
this.vleft = this.left;
this.vwidth = this.width;
break;
this.update_ratio();
horizontalmousemove(e)
if(this.drag)
// |
this.mouse = oMousePos(e);
var xdif = this.mouse.x - this.previous.x;
switch(this.flag)
case 'left':
this.vleft = this.left + xdif;
this.vwidth = this.width - xdif;
this.vtop = this.top;
this.vheight = this.height;
break;
case 'right':
this.vwidth = this.width + xdif;
this.vtop = this.top;
this.vleft = this.left;
this.vheight = this.height;
break;
this.update_ratio();
nwsemousemove(e)
if(this.drag)
// \
this.mouse = oMousePos(e);
var ydif = this.mouse.y - this.previous.y;
var xdif = this.mouse.x - this.previous.x;
switch(this.flag)
case 'topleft':
this.vleft = this.left + xdif;
this.vtop = this.top + ydif;
this.vwidth = this.width - xdif;
this.vheight = this.height - ydif;
break;
case 'lefttop':
this.vleft = this.left + xdif;
this.vtop = this.top + ydif;
this.vwidth = this.width - xdif;
this.vheight = this.height - ydif;
break;
case 'bottomright':
this.vwidth = this.width + xdif;
this.vheight = this.height + ydif;
this.vtop = this.top;
this.vleft = this.left;
break;
case 'rightbottom':
this.vwidth = this.width + xdif;
this.vheight = this.height + ydif;
this.vtop = this.top;
this.vleft = this.left;
break;
this.update_ratio();
neswmousemove(e)
if(this.drag)
// /
this.mouse = oMousePos(e);
var ydif = this.mouse.y - this.previous.y;
var xdif = this.mouse.x - this.previous.x;
switch(this.flag)
case 'topright':
this.vtop = this.top + ydif;
this.vwidth = this.width + xdif;
this.vheight = this.height - ydif;
this.vleft = this.left;
break;
case 'righttop':
this.vtop = this.top + ydif;
this.vwidth = this.width + xdif;
this.vheight = this.height - ydif;
this.vleft = this.left;
break;
case 'bottomleft':
this.vleft = this.left + xdif;
this.vwidth = this.width - xdif;
this.vheight = this.height + ydif;
this.vtop = this.top;
break;
case 'leftbottom':
this.vleft = this.left + xdif;
this.vwidth = this.width - xdif;
this.vheight = this.height + ydif;
this.vtop = this.top;
break;
this.update_ratio();
edgemouseupleave()
this.drag = false;
this.top = this.vtop;
this.left = this.vleft;
this.width = this.vwidth;
this.height = this.vheight;
mouseupleave(e)
if(super.mouseupleave(e))
this.vtop = this.top;
this.vleft = this.left;
var fp = new FlexPanel(
document.body, // parent div container
20, // top margin
20, // left margin
200, // width
150, // height
'lightgrey', // background
20, // handle height when horizontal; handle width when vertical
0.2, // edge up and left resize bar width : top resize bar width = 1 : 5
35, // green move button width and height
2, // button margin
);
/*
this method creates an element for you
which you don't need to pass in a selected element
to manipuate dom element
fp.container -> entire panel
fp.panel_el -> inside panel
*/完全实现功能需要大量的硬编码。请参考文档，它将向您展示如何将每个类用作元素。
【讨论】：
【参考方案10】：const onMouseDownEvent=(ev: React.DragEvent)=>
let imgElem = (ev.target as HTMLImageElement);
let childElem = (ev.currentTarget && ev.currentTarget.childNodes && ev.currentTarget.childNodes[0]);
let original_height = parseFloat(getComputedStyle(imgElem, null).getPropertyValue('height').replace('px', ''));
let original_width = parseFloat(getComputedStyle(imgElem, null).getPropertyValue('width').replace('px', ''));
let original_Y = imgElem.getBoundingClientRect().top;
let original_X = imgElem.getBoundingClientRect().right;
ev.preventDefault();
var original_mouse_y = ev.pageY;
var original_mouse_x = ev.pageX;
document.addEventListener('mousemove', resize);
document.addEventListener('mouseup', stopResize);
function resize(mouseMoveEvent)
const height = original_height + (mouseMoveEvent.pageY - original_mouse_y);
const width = original_width + (mouseMoveEvent.pageX - original_mouse_x);
imgElem.style.height = height + 'px';
mouseMoveEvent.target.childNodes[0].innerHTML = imgElem.style.height;
imgElem.style.width = width + 'px';
mouseMoveEvent.target.childNodes[0].innerHTML = imgElem.style.width;
function stopResize()
document.removeEventListener('mousemove', resize)
<div onMouseDown=onMouseDownEvent id="imgInCanvas" onDragStart= onDragStartFromContainer draggable="true"/>
【讨论】：
【参考方案11】：我不确定这是否是您要查找的内容，但您始终可以使用 CSS 调整大小属性并使用 javascript 将其添加到元素中；例如，假设您有一个 id 为“myDiv”的 DIV 元素，并且您希望使其可调整大小：
document.getElementById("myDiv").style.resize = "both";
以下是相关链接： Style resize Property CSS resize Property
【讨论】：
【参考方案12】：这是一个在所有边角都有调整大小助手的示例
element = document.getElementById("element")
makeResizable(element,10,10)
function makeResizable(element, minW = 100, minH = 100, size = 20)
const top = document.createElement('div');
top.style.width = '100%';
top.style.height = size + 'px';
top.style.backgroundColor = 'transparent';
top.style.position = 'absolute';
top.style.top = - (size/2) + 'px';
top.style.left = '0px';
top.style.cursor = 'n-resize';
top.addEventListener('mousedown',resizeYNegative())
element.appendChild(top);
const bottom = document.createElement('div');
bottom.style.width = '100%';
bottom.style.height = size + 'px';
bottom.style.backgroundColor = 'transparent';
bottom.style.position = 'absolute';
bottom.style.bottom = - (size/2) + 'px';
bottom.style.left = '0px';
bottom.style.cursor = 'n-resize';
bottom.addEventListener('mousedown',resizeYPositive())
element.appendChild(bottom);
const left = document.createElement('div');
left.style.width = size + 'px';
left.style.height = '100%';
left.style.backgroundColor = 'transparent';
left.style.position = 'absolute';
left.style.top = '0px';
left.style.left = - (size/2) + 'px';
left.style.cursor = 'e-resize';
left.addEventListener('mousedown',resizeXNegative())
element.appendChild(left);
const right = document.createElement('div');
right.style.width = size + 'px';
right.style.height = '100%';
right.style.backgroundColor = 'transparent';
right.style.position = 'absolute';
right.style.top = '0px';
right.style.right = - (size/2) + 'px';
right.style.cursor = 'e-resize';
right.addEventListener('mousedown',resizeXPositive())
element.appendChild(right);
const corner1 = document.createElement('div');
corner1.style.width = size + 'px';
corner1.style.height = size + 'px';
corner1.style.backgroundColor = 'transparent';
corner1.style.position = 'absolute';
corner1.style.top = - (size/2) + 'px';
corner1.style.left = - (size/2) + 'px';
corner1.style.cursor = 'nw-resize';
corner1.addEventListener('mousedown',resizeXNegative())
corner1.addEventListener('mousedown',resizeYNegative())
element.appendChild(corner1);
const corner2 = document.createElement('div');
corner2.style.width = size + 'px';
corner2.style.height = size + 'px';
corner2.style.backgroundColor = 'transparent';
corner2.style.position = 'absolute';
corner2.style.top = - (size/2) + 'px';
corner2.style.right = - (size/2) + 'px';
corner2.style.cursor = 'ne-resize';
corner2.addEventListener('mousedown',resizeXPositive())
corner2.addEventListener('mousedown',resizeYNegative())
element.appendChild(corner2);
const corner3 = document.createElement('div');
corner3.style.width = size + 'px';
corner3.style.height = size + 'px';
corner3.style.backgroundColor = 'transparent';
corner3.style.position = 'absolute';
corner3.style.bottom = - (size/2) + 'px';
corner3.style.left = - (size/2) + 'px';
corner3.style.cursor = 'sw-resize';
corner3.addEventListener('mousedown',resizeXNegative())
corner3.addEventListener('mousedown',resizeYPositive())
element.appendChild(corner3);
const corner4 = document.createElement('div');
corner4.style.width = size + 'px';
corner4.style.height = size + 'px';
corner4.style.backgroundColor = 'transparent';
corner4.style.position = 'absolute';
corner4.style.bottom = - (size/2) + 'px';
corner4.style.right = - (size/2) + 'px';
corner4.style.cursor = 'se-resize';
corner4.addEventListener('mousedown',resizeXPositive())
corner4.addEventListener('mousedown',resizeYPositive())
element.appendChild(corner4);
function get_int_style(key)
return parseInt(window.getComputedStyle(element).getPropertyValue(key));
function resizeXPositive()
let offsetX
function dragMouseDown(e)
if(e.button !== 0) return
e = e || window.event;
e.preventDefault();
const clientX = e;
offsetX = clientX - element.offsetLeft - get_int_style('width');
document.addEventListener('mouseup', closeDragElement)
document.addEventListener('mousemove', elementDrag)
function elementDrag(e)
const clientX = e;
let x = clientX - element.offsetLeft - offsetX
if(x < minW) x = minW;
element.style.width = x + 'px';
function closeDragElement()
document.removeEventListener("mouseup", closeDragElement);
document.removeEventListener("mousemove", elementDrag);
return dragMouseDown
function resizeYPositive()
let offsetY
function dragMouseDown(e)
if(e.button !== 0) return
e = e || window.event;
e.preventDefault();
const clientY = e;
offsetY = clientY - element.offsetTop - get_int_style('height');
document.addEventListener('mouseup',closeDragElement)
document.addEventListener('mousemove',elementDrag)
function elementDrag(e)
const clientY = e;
let y = clientY - element.offsetTop - offsetY;
if(y < minH) y = minH;
element.style.height = y + 'px';
function closeDragElement()
document.removeEventListener("mouseup", closeDragElement);
document.removeEventListener("mousemove", elementDrag);
return dragMouseDown
function resizeXNegative()
let offsetX
let startX
let startW
let maxX
function dragMouseDown(e)
if(e.button !== 0) return
e = e || window.event;
e.preventDefault();
const clientX = e;
startX = get_int_style('left')
startW = get_int_style('width')
offsetX = clientX - startX;
maxX = startX + startW - minW
document.addEventListener('mouseup',closeDragElement)
document.addEventListener('mousemove',elementDrag)
function elementDrag(e)
const clientX = e;
let x = clientX - offsetX
let w = startW + startX - x
if(w < minW) w = minW;
if(x > maxX) x = maxX;
element.style.left = x + 'px';
element.style.width = w + 'px';
function closeDragElement()
document.removeEventListener("mouseup", closeDragElement);
document.removeEventListener("mousemove", elementDrag);
return dragMouseDown
function resizeYNegative()
let offsetY
let startY
let startH
let maxY
function dragMouseDown(e)
if(e.button !== 0) return
e = e || window.event;
e.preventDefault();
const clientY = e;
startY = get_int_style('top')
startH = get_int_style('height')
offsetY = clientY - startY;
maxY = startY + startH - minH
document.addEventListener('mouseup',closeDragElement,false)
document.addEventListener('mousemove',elementDrag,false)
function elementDrag(e)
const clientY = e;
let y = clientY - offsetY
let h = startH + startY - y
if(h < minH) h = minH;
if(y > maxY) y = maxY;
element.style.top = y + 'px';
element.style.height = h + 'px';
function closeDragElement()
document.removeEventListener("mouseup", closeDragElement);
document.removeEventListener("mousemove", elementDrag);
return dragMouseDown
#element
position: absolute;
background-color: #f1f1f1;
border: 1px solid #d3d3d3;
left: 40px;
top: 40px;
width: 100px;
height: 100px;
border-radius: 5px;
<div id="element"></div>【讨论】：
您的答案可以通过额外的支持信息得到改进。请edit 添加更多详细信息，例如引用或文档，以便其他人可以确认您的答案是正确的。你可以找到更多关于如何写好答案的信息in the help center。【参考方案13】：var resizeHandle = document.getElementById('resizable');
var box = document.getElementById('resize');
resizeHandle.addEventListener('mousedown', initialiseResize, false);
function initialiseResize(e)
window.addEventListener('mousemove', startResizing, false);
window.addEventListener('mouseup', stopResizing, false);
function stopResizing(e)
window.removeEventListener('mousemove', startResizing, false);
window.removeEventListener('mouseup', stopResizing, false);
function startResizing(e)
box.style.width = (e.clientX) + 'px';
box.style.height = (e.clientY) + 'px';
function startResizing(e)
box.style.width = (e.clientX - box.offsetLeft) + 'px';
box.style.height = (e.clientY - box.offsetTop) + 'px';
#resize
position: relative;
width: 130px;
height: 130px;
border: 2px solid blue;
color: white;
#resizable
background-color: white;
width: 10px;
height: 10px;
cursor: se-resize;
position: absolute;
right: 0;
bottom: 0;
<div id="resize">
<div id="resizable">
</div>【讨论】：
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