<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Untitled Document</title>
        <link rel="stylesheet" type="text/css" href="css/style.css">
                <style type="text/css">
            div, span, p {
                width: 140px;
                height: 140px;
                margin: 5px;
                background: #aaa;
                border: #000 1px solid;
                float: left;
                font-size: 17px;
                font-family: Verdana;
            }

            div.mini {
                width: 55px;
                height: 55px;
                background-color: #aaa;
                font-size: 12px;
            }

            div.hide {
                display: none;
            }
        </style>
        <script type="text/javascript" src="jquery-1.7.2.js"></script>
        <script type="text/javascript">
            $(document).ready(function(){

                $("#btn1").click(function(){
                    //选取子元素, 需要在选择器前添加一个空格.
                    $("div.one :nth-child(2)").css("background", "#ffbbaa");
                });
                $("#btn2").click(function(){
                    $("div.one :first-child").css("background", "#ffbbaa");
                });
                $("#btn3").click(function(){
                    $("div.one :last-child").css("background", "#ffbbaa");
                });

                $("#btn4").click(function(){
                    $("div.one :only-child").css("background", "#ffbbaa");
                });

            });
        </script>
    </head>
    <body>
        <input type="button" value="选取每个class为one的div父元素下的第2个子元素." id="btn1"/>
        <input type="button" value="选取每个class为one的div父元素下的第一个子元素." id="btn2"/>
        <input type="button" value="选取每个class为one的div父元素下的最后一个子元素." id="btn3"/>
        <input type="button" value="如果class为one的div父元素下的仅仅只有一个子元素，那么选中这个子元素." id="btn4"/>

        <br><br>
        <div class="one" id="one">
            id 为 one,class 为 one 的div
            <div class="mini">class为mini</div>
        </div>
        <div class="one" id="two" title="test">
            id为two,class为one,title为test的div
            <div class="mini" title="other">class为mini,title为other</div>
            <div class="mini" title="test">class为mini,title为test</div>
        </div>
        <div class="one">
            <div class="mini">class为mini</div>
            <div class="mini">class为mini</div>
            <div class="mini">class为mini</div>
            <div class="mini"></div>
        </div>
        <div class="one">
            <div class="mini">class为mini</div>
            <div class="mini">class为mini</div>
            <div class="mini">class为mini</div>
            <div class="mini" title="tesst">class为mini,title为tesst</div>
        </div>
        <div style="display:none;" class="none">style的display为"none"的div</div>
        <div class="hide">class为"hide"的div</div>
        <div>
            包含input的type为"hidden"的div<input type="hidden" value="123456789" size="8">
        </div>
        <div id="mover">正在执行动画的div元素.</div>
    </body>
</html>