If you've been targeting your applications at MS Internet Explorer, you've probably been getting requests to support Firefore 3 since it's got over 8 million downloads (which hopefully translates into 8 million users) worldwide.
When starting off with web development for Firefox 3, you'll probably want to get the
Firebug and
Web Developer add-ons. They have a different feature set than the Internet Explorer Web Development toolbar so you'll probably have moments of doh-I-had-it-in-IE or cool!-IE-didnt-have-this.
A couple of commonly reported issues by web developers moving from IE to FF3 are:
- the inability to resize the file input form control
- the use of the textContent instead of the innerText property
- use of document.getElementById instead of directly referencing the element by it's ID
- really frustrated IE web developers cursing the web standards