Beta Firefox 4: new update released - how will it affect web developers?

The latest Firefox 4 beta has just been released (download it over there ). It contains hundreds of fixes , as well as Firefox Sync and Firefox Panorama . And here is a quick overview of the new web development circumstances:

• Now Firefox supports the “buffered” property in HTML5 video.
• The “autobuffer” property in HTML5 video has been replaced by “ preload ”.
• An experimental API has been added that provides more efficient javascript animations .
• Experimental CSS extension: drawing arbitrary elements as backgrounds with -moz-element.
• The default cache size has been increased (it was 50 MB, it became 250 MB, see the bug ).
• Accelerated access to some DOM properties (.id, .className, .style, ... - see bugs 584287 and 584293 ).

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^* Translator's Note: This is the fourth beta version, Gecko / 20100818 Firefox / 4.0b4.