帮我找一下错-慕课网

帮我找一下错

来源：9-4 区别getElementByID,getElementsByName,getElementsByTagName

qq_梦与现实的距离_0

2017-03-18 19:49

代码不能正常运行，各位大神帮我看看

<!DOCTYPE HTML>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>无标题文档</title>
    </head>

    <body>
        <form>
          请选择你爱好:<br>
          <input type="checkbox" name="hobby" id="hobby1"> 音乐
          <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"> 阅读
          <input type="checkbox" name="hobby" id="hobby5"> 打球
          <input type="checkbox" name="hobby" id="hobby6"> 跑步 <br>
          <input type="button" value = "全选" onclick = "checkall();">
          <input type="button" value = "全不选" onclick = "clearall();">
          <p>请输入您要选择爱好的序号，序号为1-6:</p>
          <input id="wb" name="wb" type="text" >
          <input name="ok" type="button" value="确定" onclick = "checkone();">
        </form>
        <script type="text/javascript">
        function checkall(){
            var hobby = document.getElementsByTagName("input");
           for (var i = 0; i < hobby.length; i++) {
             hobby[i].checked=true;
           }

        }
        function clearall(){
            var hobby = document.getElementsByName("hobby");

         for (var i = 0; i < hobby.length; i++) {
           hobby[i].checked=false;
         }

        }

        function checkone(){
          clearall();
            var j=document.getElementById("wb").value;
            var hobby = document.getElementsByName("hobby");
            for (var i = 0; i < j.length; i++) {
              if ((j.charAt(i)>6) || (j.charAt(i)<1)) {
                alert("越界，请重新输入！");
                document.getElementById("wb").value="";
              }
              for (var n = 0; n < j.length; n++) {
                      hobby[(j.charAt(n))-1].checked=true;
              }



        }

        </script>
    </body>
</html>