Trouble with Form validation code

[Jaye]

Hi. I'm having some trouble with the code I'm using to validate a form. The form is used to query a database and users can enter multiple search criteria separated by commas. Since search criteria varies, some fields may be left blank, however, I want to prevent an empty form from being submitted. I have written the code, but it's not working. I have changed it several times and now I'm just getting more and more confused. I'm new to javascript, so there could be a million syntax errors in here. The error that I am getting now is this:

"elements.numva rs.value" is null or not an object

I looked the error up and tried the fixes that were suggested, but still no luck. Here is the code for the javascript function:

function Validate_Form(form) {
   var checkvars = 0;
   for (i = 1; i <= form.elements["numvars"].value; i++) 
   {
      if (form.elements["vr" + i].checked == true)
         checkvars++;
   }
   if (checkvars == 0)
   {
      alert("No variables have been selected.");
      return (false);
   }
document.queryf.submit();
   }

And here is the code for the form tag:

<form NAME="queryf" action="submit_query.asp" method="post" onsubmit="javascript:return Validate_Form(this);">

Any help would be greatly appreciated, thanks!

Jaye

[dorinbogdan]

Make sure that the "numvars" element exist on the form and it has a value property.

[Jaye]

Thanks for the quick reply!

I checked the form for the numvars value, and it's not in the form, so that explains the error. I must have deleted it in the course of cutting and pasting snippets of code here and there.

I think I am going to start the whole thing from scratch and see how it goes. I found a good beginner's article on form validation, so I'll go through that and see if I can get this to work properly.

Thanks again for your help.