PHP page error messages suddenly disappeared in Firefox

Must have changed something somewhere, but darned if I can find it. The form creates errors at the top of the page which now don’t appear except for the top two data fields. Any ideas if something has changed in Firefox that might account for it

Just to add some detail, I’ve been playing with it, taking bits out of the code until the fault went away.

The original code came from

To clarify, if you click the submit button without entering any data, in IE you see a whole list of error messages highlighted in yellow at the top of the form, but do the same in Firefox all you get is an error under the name field and the e-mail field. The only way to get this to stop happening is to remove the <script type=‘text/javascript’ src=‘scripts/gen_validatorv31.js’></script> from the HEAD tag section of the page. The form still seems to validate and the correct errors appear, but I don’t know why it’s happening.

It all worked fine until Firefox updated to version 13, so has anything in the way FF handles javascript changed that would cause this does anyone know?