The page will check if your browser supports HTML5 parsing, canvas, file drag-and-drop, embedded audio and video, and all of the other elements required by the draft HTML5 specification, as well as specifications that are related to HTML5 but not actually a part of it, like geolocation and local storage.

You’ll be issued a score (out of a total of 300 points) that indicates the level of support for the stuff in the spec, as well as bonus points for support that goes beyond what’s required for HTML5 compliance. For example, your browser gets bonus points for each video codec and audio codec included in the browser. These are only bonus points, and not real points, since HTML5 outlines how audio and video files can be embedded on a page, but does not require a specific audio or video codec to be included.

Here’s how the browsers on my Mac stack up:

• Chrome (dev channel) scores 217 points and 10 bonus points
• Safari 5.01 scores 208 points with 6 bonus points
• Firefox 4 beta 2 scores 189 points with 9 bonus points
• Opera 10.6 scores 159 points and 7 bonus points
• Internet Explorer 9 platform preview scores 84 points and 1 bonus point

If you’re wondering how these scores are being generated, the code behind the single-serving app was posted to Github by creator Niels Leenheer. He says he also incorporated the HTML5 parser tests created by Mozilla developer Henri Sivonen.

HTML5, the much-anticipated rewrite of the web’s lingua franca, is currently in open development, with the web’s standards body and all the browser vendors taking part. While some browsers won’t fully support HTML5 until it is officially standardized some time in the next year or two, developers have already begun building with it, and all major browser vendors are adding support into their latest releases.

There are multiple methods of checking for HTML5 element support when a user visits your page, as well as libraries like Modernizr, which let you take advantage of HTML5 elements while controlling how browsers with limited support handle your page.

The HTML5 specification is updated frequently, and browser support for the various elements is in constant flux. As such, the test numbers will go up and down as new browser versions are released and as the code that powers the tests is improved and is updated to reflect HTML5’s changing status.

Also, Leenheer has posted the next version of the test, which ups the total possible score to 315 points, at beta.html5test.com. Go there if you want to see what the page will be testing for in the future.