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+" "; 38 } 39 </script> 40 </body> 41 </html>