求助！一个代码加个判断！

解决方案 »

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<script>
    function sub(){
        var checkall = true
        var chs = document.getElementsByName('n');
            for(var i=0; i <chs.length; i++){
                if(!chs[i].checked)
                    checkall |= false;
            }
        if(!checkall){
            alert('请全部选勾');
            return false;
        }
        location.href='job.asp?job=2'
    }
</script>
.........
<input type="submit" name="button" id="button" value="同意以上协议，并开始注册" onclick="return sub()" />
是不是这个效果
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
  <TITLE> New Document </TITLE>
  <META NAME="Generator" CONTENT="EditPlus">
  <META NAME="Author" CONTENT="">
  <META NAME="Keywords" CONTENT="">
  <META NAME="Description" CONTENT="">
</HEAD> <BODY>
  <script>
    function sub(){
        var chs = document.getElementsByName('n');
            for(var i=0; i <chs.length; i++)
{
if(!chs[i].checked)
{
alert("请全部勾选");
return;
}

}
        location.href='job.asp?job=2'
    }
</script>
<input type="checkbox" name="n" id="n" />
<input type="checkbox" name="n" id="n" />
<input type="checkbox" name="n" id="n" />
<input type="submit" name="button" id="button" value="同意以上协议，并开始注册" onclick="sub()" />  </BODY>
</HTML>
<script>
    function sub(){
        var chs = document.getElementsByName('n');
            for(var i=0; i <chs.length; i++)
{
if(!chs[i].checked){
alert("请全部选勾")
  return false;
  }
}
        location.href='job.asp?job=2'
    }
</script>