I have a site. It works.

I amended the site to stop using bloated code, and implemented Jquery corners, as well as some "cool" gradients.

I then implemented some php code to stop spammers (html entities).

The spam stopped, I was happy.

However, the login form stopped working too. It works in Firefox, but not Internet Explorer. I'm not quite sure why this is, but I need to know so that I can get any bad coding practices out of my system.

I have not added or removed any of the login php (not even for spam purposes). I have not added or removed any of the login Javascript.

I really don't have a clue where to start looking with this or even what to Google.