HTML 5 support in Firefox 4

Does Firefox fully support HTML5 APIs? I have seen in some other questi开发者_StackOverflowons (I cannot remember where) that BlobBuilder is not supported in Firefox.

In addition, when I try to use BlobBuilder object in JavaScript, I am getting an error says "BlobBuilder is not defined". I am using Firefox 4.0b7 version for HTML5 based development.

Given that searching MDC for BlobBuilder turned up no results, and that on the latest daily build (Firefox 4b13), running BlobBuilder resulted in a reference error, I believe that this API will not be implemented in Firefox 4 when it comes out of beta (which will be very soon, given that no blockers remain)

http://www.caniuse.com/#cats=HTML5,JS_API

Looks like recent versions of FireFox support almost everything in HTML5 (including API's)