I have a PHP form that is submitted via email. I have been having some random problems with the emails showing up. About 20% of the emails don't show up. I've heard PHP is not well-supported by some alternative browsers such as Mozilla and Firefox. Is anyone aware of similar problems with Mozilla/ Firefox? Any advice?

PHP is a server side scripting language, and as a result, it is not affected by browser choice.

The reason your emails are not being received is likely a problem with the server on which the emails are being delivered to, or a problem with the form processing script.

Can you show us the form and the form processing script?