fix this javascript code

First things first, Ian is right.  The best place to ask JS question would be on a JS forum, not a CF forum. Still, we can tie CF into this shortly, so that'll get things back on topic.  This isn't to be obstructive, just a tip to think about what one is actually asking about before deciding which forum to ask it on.

Secondly... are you wanting to validate a NUMERIC or an INTEGER?  You're using parseInt(), which would suggest an intenger, but you speak more broadly of numeric values too.

Note to Ian: validating for an int with a regex... you don't want ANY decimal points ;-)

Now for the CF tie in.  If you want JS that works with either integer or more general numeric validation, don't try to reinvent the wheel.  CF already provides the JS to do this with <cfinput> and <cfform>.  Even if you don't want to use those constructs, there's nothing to stop you lifting the JS out.

--

Adam

<script type="text/javascript">
function checkVar() {
    var field = document.myForm.mpresent;
    var mpre = parseInt(field.value);
    if (isNaN(mpre)) {
        alert("You Must Enter Numeric Value In Members Present Value.");

        return false;
    }
    return true;
}
</script>
<form name="myForm" >
<input name="mpresent" type="text">
</form>

A question more natural to a JavaScript list rathen then a ColdFusion list.

But, What I prefer to do is check the for allowed characters with regex.

Untested code:

var numbers = new RegExp("[^0-9.]"); // Find any character that is not 0-9 or a period.
if (number.test(field.value)){
  alert("Fail, found characters that where something other then 0 through 9 or a decimal point.");
}