1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
2 <html>
3 <head>
4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
5 <script type="text/javascript" src="../js/jquery-1.4.2.js"></script>
6 <title>test</title>
7 </head>
8 <body>
9 <input type="text" id="username" value="asdf">
10 <script type="text/javascript">
11
12 var $jq=$("#username");
13 alert($jq.val());
14 // 以下两种方式等同
//jQuery转换成 dom对象
15 var dom1=$jq[0];
16 var dom2=($jq).get(0);
17 alert(dom1.value);
18 alert(dom2.value);
19 //转换 dom对象转换成jQuery对象
20 var $jj=$(dom1);
21 alert($jj.val()+"wwwwwwww");
22 </script>
23 </body>
24 </html>
