Interview: Firefox 3's interface design guru talks

Was the original impetus for Mozilla when Microsoft dropped the ball with Internet Explorer?

"Yes, definitely. And it wasn't just that they gave up on the web, it was that the web showed a lot of promise and then began to get stagnant. We kept hearing from web developers. Brenden Eich, who is the creator of JavaScript – which I believe was a weekend side project for him back in the early days – decided that we needed an interpreted language to make the web sing and dance, so he created it.

"He was really frustrated seeing the potential of JavaScript wasted. That was what really founded the Mozilla organisation and made us come up with a clear mission of supporting choice and freedom on the Internet. While we won't draw any direct causal links, we will observe publicly that when Mozilla and Firefox started gaining popularity, that was when you started seeing things like Web 2.0, really powerful applications and mash-ups – you saw people doing really innovative things on the web."

How do you play the game of watching something gain in popularity without being really sure if will become a standard?

"It's a real balancing act. The best way to make sure it's working is to keep open lines of communication with web developers and people using the websites – keeping the dialogue going. That is one advantage of being an open source company.

"I'll give you an example of something that happened in Firefox 3. Cross-site scripting is a pretty common request from website developers; the ability for website A to talk to website B. The only way they can do it right now is to do a full include of website B's scripts libraries, and since the same domain principles have been around on the web for a while, that opens things up to a host of nasty side effects and attacks.

"So we have had security researchers who are web developers themselves – from Stanford – come and talk to us about better ways of doing this. And one of them was an emerging standard called post message. And this is very much like what you are talking about; there is no way of knowing if post message was going to be a successful standard.

"These guys came by and talked about how it was going to be easy for people to use, and we decided pretty late in the cycle to invest in post message. What it does is it lets website A send a message directly to website B with just a bit of structured data and no code – a much more secure way of doing it. This is an example of how we are trying this bi-directional dialogue with developers and users to make sure we are supporting standards that we know there is a demand for and a usage for. Some others we just know are good standards to support.

"HTML 5 offline is another example of this – we saw people clamouring for offline apps, so this was one we thought was worth investing in. Others, we're not so sure. There's an emerging standard online called microformats, and we have partial support for it in Firefox 3, so our engine is able to detect them, pull them out of data objects and offer them to add-ons and to any application built on the engine to use. But we haven't actually exposed any UI for it, because we're not sure how the web is going to make use of them yet. So there we are tentative and waiting to see what happens on the web."

My impression is that Mozilla can be a little tight lipped with information. As an open source company, how open are you? What are you not open about?