Javascript value refresh

I have some web pages with text fields. I validate the fields with a javascript by looking at the values. This worked in IE and Netscape browsers. I edited the pages and now it does not work in Netscape browsers. The netscape browser is looking at the loaded value of the field not the entered value. The only thing I edited on the pages was to remove a background gif and its height and width but I can’t think of why that would cause a problem. ?