1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta charset="UTF-8">
 5     <title></title>
 6     <style type="text/css">
 7         body {
 8             font-size: 12px;
 9         }
10 
11         fieldset {
12             width: 260px;
13         }
14 
15         #tip {
16             margin: 8px 0px;
17             padding: 5px;
18             border: solid 1px #ffdb15;
19             background-color: #ffe6da;
20             color: #666;
21             display: none;
22         }
23     </style>
24     <script type="text/javascript" src="js/system.js"></script>
25 </head>
26 <body>
27 <fieldset>
28     <legend>检测奇偶性</legend>
29     <input type="text" id="txtN"/>
30     <input type="button" value="检测" id="blnC">
31 
32     <div id="tip"></div>
33 </fieldset>
34 <script type="text/javascript">
35     var time = 1, HTML = "";
36     $$("blnC").onclick = function () {
37         if (time <= 5) {
38             var $n = $$("txtN").value;
39             if (Number($n)) {                              //判断是否是数字
40                 HTML = ($n % 2) ? "奇数" : "偶数";
41             } else {
42                 HTML = "你输入的不是数字！";
43             }
44             time++;
45         } else {
46             HTML = "今天你已经超过5次了！";
47         }
48         $$("tip").style.display = "block";
49         $$("tip").innerText = HTML;
50     }
51 </script>
52 </body>
53 </html>