Internet Explorer (at least through v8) don't support the canvas tag, which jMockups is built on. Most web developers and designers don't use IE, so I don't think I'm giving up too much by not supporting it.
Plus, you can share your mockups with anyone regardless of their browser so it shouldn't be an issue for most of the target audience.
Edit: also, great job on the app. Branding could use some work (i.e. the name) but I think this is well beyond my expectations. I was about to pay for a balsamiq license today, but I'd rather have this. Any idea for license costs?
The Google Chrome engine looks great, but I imagine most of the people who understand why its important are already using one of the other browsers. Regardless, I'll check it out--thanks for the pointer.
Naming it was tricky. Originally I was going to use leandesigns.com, but the name was trademarked. The j jMockups is for JavaScript (think jQuery).
As far as price, jMockups is free for up to 5 mockups and $24/mo for up to 200.
If you have any questions you can contact me at matt@jmockups.com.
Some numbers to back this up. We run http://www.domestika.org - the largest spanish-speaking community for designers with some.
There we have around 19% using IE and the rest on Firefox, Safari and Chrome.
If you assume that at least some of the IE users would be happy to download Firefox, Chrome or Safari when using a specific tool and you can get at least some more to install chrome frame, the percentage of IE users left means that for this kind of audience it really doesn't make sense trying to work around the limitations of that browser...
No