                        課程
                    
                        /前端開發
                        
                            /JavaScript
                        
                        /JavaScript進階篇

我這個怎么最后一個不能運行呢？

<!DOCTYPE HTML>
<html>
??? <head>
??????? <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
??????? <title>無標題文檔</title>
??? </head>
???
??? <body>
??????? <form>
????????? 請選擇你愛好:<br>
????????? <input type="checkbox" name="hobby" id="hobby1">? 音樂
????????? <input type="checkbox" name="hobby" id="hobby2">? 登山
????????? <input type="checkbox" name="hobby" id="hobby3">? 游泳
????????? <input type="checkbox" name="hobby" id="hobby4">? 閱讀
????????? <input type="checkbox" name="hobby" id="hobby5">? 打球
????????? <input type="checkbox" name="hobby" id="hobby6">? 跑步 <br>
????????? <input type="button" value = "全選" onclick = "checkall();">
????????? <input type="button" value = "全不選" onclick = "clearall();">
????????? <p>請輸入您要選擇愛好的序號，序號為1-6:</p>
????????? <input id="wb" name="wb" type="text" >
????????? <input name="ok" type="button" value="確定" onclick = "checkone();">
??????? </form>
??????? <script type="text/javascript">
??????? function checkall(){
??????????? var hobby = document.getElementsByTagName("input");
??????????
??????????? for(i=0;i<hobby.length;i++){
??????????????? hobby[i].checked=true;
??????????? }? // 任務1
??????????
??????? }
??????? function clearall(){
??????????? var hobby = document.getElementsByName("hobby");
???????????
??????????? for(i=0;i<hobby.length;i++){
??????????????? hobby[i].checked=false;
??????????? }// 任務2???
???????????
??????? }
???????
??????? function checkone(){
??????????
??????????? var j=document.getElementById("wb").value;
??????????? var hobby = document.getElementsByName("hobby");
??????????? switch("j"){
??????????????? case 1:
??????????????????? hobby[0].checked=true;
??????????????????? break;
??????????????? case 2:
??????????????????? hobby[1].checked=true;
??????????????????? break;
??????????????? case 3:
??????????????????? hobby[2].checked=true;
??????????????????? break;
??????????????? case 4:
??????????????????? hobby[3].checked=true;
??????????????? case 5:
??????????????????? hobby[4].checked=true;
??????????????????? break;
??????????????? case 6:
??????????????????? hobby[5].checked=true;
??????????????????? break;
??????????? }// 任務3
???????
??????? }
???????
??????? </script>
??? </body>
</html>