JQ——遍历(each遍历数组遍历)添加(appendappendTo)

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jQuery的隐式迭代是对同一类型的元素做了相同的操作,如果想要给同一元素做不同的操作,就要用到遍历

1、each实现遍历操作:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>each实现的遍历</title>
        <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
            $(function(){
                $("button").click(function(){
                $("li").each(function(){
                alert($(this).text())
                    });
                });
            });
        </script>
    </head>
    <body>
        <button>点击按键,each实现遍历操作</button>
            <ul>
            <li>2020</li>
            <li>新年好!</li>
            <li>武汉加油!</li>
            </ul>
    </body>
</html>

 

 2、遍历数组:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>数组遍历</title>
        <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
            $(function () { 
                $.each([213,37,34,567,2020], function(index, value) {
                      alert(index + \': \' + value);
            });
        })
        </script>
    </head>
    <body>
        
    </body>
</html>

函数中,index代表角标,value代表遍历的每一个元素。

 

 

 

 

 

 ... ...

3、append实现添加操作(在被选元素的末尾添加)

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>append实现添加操作</title>
        <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
        $(function(){
            $("#button").click(function(){
                $("ul").append("<li>武汉加油!</li>");
            });
        });
        </script>
    </head>
    <body>
        <button id="button">append添加</button>
        <ul>
            <li>2020</li>
            <li>新年好!</li>
            <li>武汉加油!</li>
        </ul>
    </body>
</html>

 

4、appendTo实现添加操作:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>appendTo实现添加操作</title>
        <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
        $(function(){
            $("#button").click(function(){
                $("<li>武汉加油!</li>").appendTo("ul");
            });
        });
        </script>
    </head>
    <body>
        <button id="button">append添加</button>
        <ul>
            <li>2020</li>
            <li>新年好!</li>
            <li>武汉加油!</li>
        </ul>
    </body>
</html>

 

 5、empty() 方法:移除被选元素内部的的所有子节点和内容

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>empty实现移除操作</title>
        <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
        $(function(){
            $("#button").click(function(){
                $("ul").empty();
            });
        });
        </script>
    </head>
    <body>
        <button id="button">empty移除</button>
        <ul>
            <li>2020</li>
            <li>新年好!</li>
            <li>武汉加油!</li>
            <ol>新年快乐!</ol>
        </ul>
    </body>
</html>

点击按键前:

 

 点击按键后:

 

 ul内部的所有元素被移除,文字部分消失了。

6、remove() 方法:移除相匹配的元素所有的文本和子节点

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>remove实现移除操作</title>
        <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
        $(function(){
            $("#button").click(function(){
                $("li").remove();
            });
        });
        </script>
    </head>
    <body>
        <button id="button">remove移除</button>
        <ul>
            <li>2020</li>
            <li>新年好!</li>
            <li>武汉加油!</li>
            <ol>新年快乐!</ol>
        </ul>
    </body>
</html>

点击按键前:

 

 点击按键执行移除操作后:

 

 只剩下ol元素内部的内容,li内部的内容已被移除。

 7、案例(省市二级联动):

(1)核心代码:

<script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
            $(function(){
            var cities = new Array(11);
            cities[0] = new Array("东城区","西城区" ,"崇文区", "宣武区" ,"朝阳区" ,"丰台区","石景山区" ,"海淀区门" ,"头沟区");
            cities[1] = new Array();
            cities[2] = new Array();
            cities[3] = new Array();
            cities[4] = new Array();
            cities[5] = new Array();
            cities[6] = new Array();
            cities[7] = new Array();
            cities[8] = new Array();
            cities[9] = new Array();
            cities[10] = new Array();
            cities[11] = new Array();
                $("#province").change(function(){
                    $("#city").empty();
                    var val = this.value;
                    $.each(cities,function(i,n){
                        if(val==i){//i为下标,n为当前的省份
                            $.each(cities[i], function(j,m) {
                                var textNode = document.createTextNode(m);
                                var opEle = document.createElement("option");
                                $(opEle).append(textNode);//对象的转换
                                $(opEle).appendTo($("#city"));
                            });
                        }
                    });
                });
            });
        </script>

此函数用到了用JQ的函数对二维数组进行遍历(each)、DOM操作、DOM对象向JQ对象的转化、清除(empty)。

 (2)完整代码:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>省市二级联动</title>
       <script type="text/javascript" src="../js/jquery-1.8.3.js" ></script>
        <script>
            $(function(){
            var cities = new Array(11);
            cities[0] = new Array("东城区","西城区" ,"崇文区", "宣武区" ,"朝阳区" ,"丰台区","石景山区" ,"海淀区门" ,"头沟区");
            cities[1] = new Array();
            cities[2] = new Array();
            cities[3] = new Array();
            cities[4] = new Array();
            cities[5] = new Array();
            cities[6] = new Array();
            cities[7] = new Array();
            cities[8] = new Array();
            cities[9] = new Array();
            cities[10] = new Array();
            cities[11] = new Array();
                $("#province").change(function(){
                    $("#city").empty();
                    var val = this.value;
                    $.each(cities,function(i,n){
                        if(val==i){//i为下标,n为当前的省份
                            $.each(cities[i], function(j,m) {
                                var textNode = document.createTextNode(m);
                                var opEle = document.createElement("option");
                                $(opEle).append(textNode);//对象的转换
                                $(opEle).appendTo($("#city"));
                            });
                        }
                    });
                });
            });
        </script>
            
    </head>
    <body>
        <table border="1px" align="center" width="1300px" cellpadding="0px" cellspacing="0px">
            <tr>
                <td height="600px" ">
                    <form action="#" method="get" name="regForm" onsubmit="return checkForm()">
                        <table border="1px" width="450px" height="400px" align="center" cellpadding="0px" cellspacing="0px" bgcolor="white">
                            <tr>
                                <td>
                                            用户名
                                </td>
                                <td>
                                    <input type="text" name="user" size="34px" id="user" 
                                        onfocus="showTips(\'user\',\'用户名必填!\')" 
                                        onblur="check(\'user\',\'用户名不能为空!\')"/>
                                        <span id="userspan"></span>
                                </td>
                            </tr>
                            
                            <tr>
                                <td>
                                    密码
                                </td>
                                <td>
                                    <input type="password" name="password" size="34px" id="password"  
                                        onfocus="showTips(\'password\',\'密码必填\')"
                                        onblur="check(\'password\',\'密码不能为空!\')"/>
                                        <span id="passwordspan"></span>
                                </td>
                            </tr>
                            
                            <tr>
                                <td>
                                    确认密码
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