<script language="javascript">

function test() {

    var LEN =  document.getElementById("qty").value; 

   for(var i=1; i<=LEN ; i++) {
        if(document.getElementById("weeknumber" + i).value=="") {
             alert("周别不能为空!")
document.getElementById("weeknumber" + i).focus();

return false;

        }
   }
  

}
</script>


<form id="form1" name="form1" method="post" action="">
<% for i=1 to 5 %>
<input type="text" name="weeknumber<%=i%>" id="weeknumber<%=i%>"/><br />
<% next %>
<input name="qty" id="qty" type="hidden" value="<%= i-1%>" />
<input type="submit" name="button" id="button" value="提交" onclick="test();" />

</form>