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I briefly blogged earlier this year about our internal project that allowed us to write Firefox extensions using the Google Web Toolkit framework. I’m happy to say that I’ve just pushed out the first version of the code for developers to start playing with.

GWT 2.0 ships with a new HtmlUnit-based testing system that makes testing faster, but isn’t full web-browser under the hood. It can’t perform layout, so any tests that rely on layout measurements won’t succeed.

There are a number of alternate run styles that are useful, however. Manual mode, which outputs a URL that you can connect any browser to, works well for quick testing, but is a pain when you need to keep running it over and over. RemoteWeb and Selenium automate the process of starting and stopping browsers, but require you to start an external server before testing.

I went down to Mountain View last week to show off the company we’ve been building, DotSpots, plug our brand-new Chrome extension and demo some of the great new features of GWT 2.0.

See it directly on YouTube here:

Kudos to the Google team for putting together such a great event. You don’t realize how much planning and preparation goes into an hour-long event like that.

UPDATE (Jan 6, 2010): The Chrome team has turned on extensions on Mac in the latest dev channel build. Even better, you can install directly from extension pages without this bookmarklet. Hooray!

We just officially launched our extension on the Chrome extension gallery today and Mac users are having trouble installing the extension. The ‘Install’ button for Chrome extensions is disabled if you are running on a Mac.

You can manually download extensions from the Google download site using a URL like so:

https://clients2.google.com/service/update2/crx?response=redirect&x=id%3Danfibeojfgdfejcfflalkebdfgojfbbm%26uc.

Occasionally it becomes useful to get the absolute form path of a URL from a relative one. You might be dynamically changing links on a page, or loading scripts from the same location as scripts that have already been loaded.

Computing an absolute URL by hand is problematic: you need to deal with any <base> elements in the document and properly implement the relative path canonicalization that browsers already do.

It turns out that on standards-compliant browsers based on Gecko, WebKit or Opera, the href property of anchor elements is magical. If you assign a URL fragment to it, it comes back as a fully-qualified URL when you read it back.