This week, Mozilla's whirlwind release cycle yielded the first release candidate of Firefox 5 in the beta channel, just a matter of a week before the final version is expected to be released.

Changes in this version include: Support for CSS animations; a more prominent Do-Not-Track header preference; improved canvas, JavaScript, memory, and networking performance; Improved standards support for HTML5, XHR, MathML, SMIL, and canvas, improved desktop environment integration for Linux users; and more.

Since WebGL security is a hot issue at the moment, Firefox v5 RC no longer supports cross-domain textures, according to the WebGL spec that was updated earlier in this month.

"Imagine that you currently have a session open on your bank's website, allowing you to download scanned copies of cheques you've written," explained Benoit Jacob in the Mozilla blog, "You don't want scripts loaded in other tabs, from other websites, to be able to read your scanned cheques! Similarly, when you draw a cross-domain image onto a 2D canvas, using drawImage(), the canvas becomes 'tainted' so that it's no longer possible for scripts to read its pixels. This prevents a loophole whereby a canvas would be used as a proxy to read cross-domain images."

Download Firefox 5 RC for Windows in Fileforum now!