1 <!DOCTYPE html>
2 <html lang="en">
3 <head>
4 <meta charset="UTF-8">
5 <title>课程</title>
6 </head>
7 <body>
8 <select id="myCourse" onchange="getCourse();">
9 <option value="" selected>--请选择一门课程---</option>
10 </select>
11 <textarea id="myares" cols=30 rows="10"></textarea>
12 <script type="text/javascript">
13 var last_select_num=3;//从数据库中查询，发现用户上次选择了3门课程
14 //动态添加第一门课程java
15 var myOption=document.createElement("OPTION");
16 myOption.value="java";
17 myOption.text="java";
18 myCourse.add(myOption);
19 //动态添加第二门课程js
20 var myOption=document.createElement("OPTION");
21 myOption.value="js";
22 myOption.text="js";
23 myCourse.add(myOption);
24 //动态添加第三门课程vs
25 var myOption=document.createElement("OPTION");
26 myOption.value="vs";
27 myOption.text="vs";
28 myCourse.add(myOption);
29 //动态添加第四门课程vs
30 var myOption=document.createElement("OPTION");
31 myOption.value="vb";
32 myOption.text="vb";
33 myCourse.add(myOption);
34
35 function getCourse(){
36 //注意这种方式的结果，有什么区别
37 myares.value+="你选中了1："+myCourse.value+"\r\n";
38 }
39 </script>
40 </body>
41 </html>
