javascript null

[tito]

I have an ajax application, it works fine. However, I put this code to verify that a number has a value

if (isNaN(form.H.value) || isNaN(form.A.value))
{
alert("Please use numbers only.");
return false;
}

That works fine when you put a letter in the input box.

However, if someone does a blank submit with value=""

it goes thru. I tried using 'undefined', that does not work.

Please how can I fix the above code to prevent empty values?

Thank you.

[tito]

Never mind, thanks