1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
2 <html xmlns="http://www.w3.org/1999/xhtml">
3 <head>
4 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
5 <title>jQuery+JavaScript 实现 table 的增加和减少</title>
6 <script language="javascript" src="jquery-1.7.1.min.js"></script>
7 </head>
8 <body>
9 <p><input type="text" value="请输入邮箱地址" id="email" id="email" /></p>
10 <p><input type="button" value="提交" /></p>
11 <script type="text/javascript">
12 $("#email").focus(function(){
13 var email_txt = $(this).val();
14 if (email_txt == this.defaultValue) {
15 $(this).val("");
16 }
17 })
18 $("#email").blur(function(){
19 var email_txt = $(this).val();
20 if (email_txt == "") {
21 $(this).val(this.defaultValue);
22 }
23 })
24 </script>
25 </body>
26 </html>
