Codenamed Shiretoko, Firefox 3.1 Alpha 1 has been released and includes added features for developers as well as GUI changes.

Web standards improvements in the Gecko layout engine

Text API for the <canvas> element

The <canvas> element seems to be a very convenient way of generating images on the fly, and with the new Text API the element just got even better. I am afraid, though, of the potential misuse of this (using <canvas> to generate fancy headers, for example).

Support for using border images

Now this is amazing. Reading through the W3C editor’s draft, rounded corners just became a whole lot easier. Of course, rounded corners is only the tip of the iceberg when you can use images as a border. The implementation is interesting - the image to be used as a border is sliced up into nine pieces in a three-by-three grid (the size of the rows and columns are set through CSS). The corresponding border slices are then used in the corresponding positions of the styled element, stretched or repeated as per CSS code.

An image like this

could be used to make a border like this

(Images taken from the W3C example.)

Support for Javascript query selectors

In short, query selectors allow Javascript to use CSS selectors as an argument in a function to select certain elements. Read the Selectors API (linked above) for more.

Several improvements to the Smart Location Bar

You can now restrict the results shown by typing certain key characters after your query:

• “^” for history
• “*” for bookmarks
• “+” for tagged pages
• “@” for matching URL only
• “#” for matching title/tags only

This is in addition to some about:config setttings you can change. Again, follow through to the above link for more.

A new tab switching behavior

I’m rather lukewarm about this feature. I love being able to ctrl+tab through my tabs, in the order they are shown on my screen. With the new tabbing behavior, ctrl+tab brings you to your last active tab - repeating ctrl+tab would let you toggle between two tabs. Also, it brings a new feature of showing tab previews, much like that of Vista.

I’m going to have to move from ctrl+tab to ctrl+pageDn, which does the same thing as the original ctrl+tab. It’s a bit more reaching for my fingers, but I guess I can suck it up. The previews aren’t that hot either, and flash content doesn’t show up at all. All in all, I think this is a feature that isn’t completely necessary and should be left as a plug-in.

via Mozilla Developer Center