html 在dom中遍历叶节点
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<head>
<script type="text/javascript">
function GetNextLeaf (node) {
while (!node.nextSibling) {
node = node.parentNode;
if (!node) {
return node;
}
}
var leaf = node.nextSibling;
while (leaf.firstChild) {
leaf = leaf.firstChild;
}
return leaf;
}
function GetPreviousLeaf (node) {
while (!node.previousSibling) {
node = node.parentNode;
if (!node) {
return node;
}
}
var leaf = node.previousSibling;
while (leaf.lastChild) {
leaf = leaf.lastChild;
}
return leaf;
}
// If the text content of an element contains white-spaces only, then does not need to colorize
function IsTextVisible (text) {
for (var i = 0; i < text.length; i++) {
if (text[i] != ' ' && text[i] != '\t' && text[i] != '\r' && text[i] != '\n')
return true;
}
return false;
}
function ColorizeLeaf (node, color) {
if (!IsTextVisible (node.textContent))
return;
var parentNode = node.parentNode;
// if the node does not have siblings and the parent is a span element, then modify its color
if (!node.previousSibling && !node.nextSibling) {
if (parentNode.tagName.toLowerCase () == "span") {
parentNode.style.color = color;
return;
}
}
// Create a span element around the node
var span = document.createElement ("span");
span.style.color = color;
var nextSibling = node.nextSibling;
parentNode.removeChild (node);
span.appendChild (node);
parentNode.insertBefore (span, nextSibling);
}
function ColorizeLeafFromTo (node, color, from, to) {
var text = node.textContent;
if (!IsTextVisible (text))
return;
if (from < 0)
from = 0;
if (to < 0)
to = text.length;
if (from == 0 && to >= text.length) {
// to avoid unnecessary span elements
ColorizeLeaf (node, color);
return;
}
var part1 = text.substring (0, from);
var part2 = text.substring (from, to);
var part3 = text.substring (to, text.length);
var parentNode = node.parentNode;
var nextSibling = node.nextSibling;
parentNode.removeChild (node);
if (part1.length > 0) {
var textNode = document.createTextNode (part1);
parentNode.insertBefore (textNode, nextSibling);
}
if (part2.length > 0) {
var span = document.createElement ("span");
span.style.color = color;
var textNode = document.createTextNode (part2);
span.appendChild (textNode);
parentNode.insertBefore (span, nextSibling);
}
if (part3.length > 0) {
var textNode = document.createTextNode (part3);
parentNode.insertBefore (textNode, nextSibling);
}
}
function ColorizeNode (node, color) {
var childNode = node.firstChild;
if (!childNode) {
ColorizeLeaf (node, color);
return;
}
while (childNode) {
// store the next sibling of the childNode, because colorizing modifies the DOM structure
var nextSibling = childNode.nextSibling;
ColorizeNode (childNode, color);
childNode = nextSibling;
}
}
function ColorizeNodeFromTo (node, color, from, to) {
var childNode = node.firstChild;
if (!childNode) {
ColorizeLeafFromTo (node, color, from, to);
return;
}
for (var i = from; i < to; i++) {
ColorizeNode (node.childNodes[i], color);
}
}
function ColorizeSelection (color) {
if (window.getSelection) { // all browsers, except IE before version 9
var selectionRange = window.getSelection ();
if (selectionRange.isCollapsed) {
alert ("Please select some content first!");
}
else {
var range = selectionRange.getRangeAt (0);
// store the start and end points of the current selection, because the selection will be removed
var startContainer = range.startContainer;
var startOffset = range.startOffset;
var endContainer = range.endContainer;
var endOffset = range.endOffset;
// because of Opera, we need to remove the selection before modifying the DOM hierarchy
selectionRange.removeAllRanges ();
if (startContainer == endContainer) {
ColorizeNodeFromTo (startContainer, color, startOffset, endOffset);
}
else {
if (startContainer.firstChild) {
var startLeaf = startContainer.childNodes[startOffset];
}
else {
var startLeaf = GetNextLeaf (startContainer);
ColorizeLeafFromTo (startContainer, color, startOffset, -1);
}
if (endContainer.firstChild) {
if (endOffset > 0) {
var endLeaf = endContainer.childNodes[endOffset - 1];
}
else {
var endLeaf = GetPreviousLeaf (endContainer);
}
}
else {
var endLeaf = GetPreviousLeaf (endContainer);
ColorizeLeafFromTo (endContainer, color, 0, endOffset);
}
while (startLeaf) {
var nextLeaf = GetNextLeaf (startLeaf);
ColorizeLeaf (startLeaf, color);
if (startLeaf == endLeaf) {
break;
}
startLeaf = nextLeaf;
}
}
}
}
else {
// Internet Explorer before version 9
alert ("Your browser does not support this example!");
}
}
</script>
</head>
<body>
Select some content on this page and use the buttons below to colorize the selected text.<br /><br />
<button onclick="ColorizeSelection ('#FF0000');">Set color to red!</button>
<button onclick="ColorizeSelection ('#0000FF');">Set color to blue!</button>
<br />
<div>Some text for selection</div>
<div><b>Some bold text for selection.</b></div>
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