The current working spec for the HTML5 standard has a lot of exciting features we would eventually like to implement in WebKit. One feature we felt was exciting enough to tackle now even though the spec is still in flux is client-side database storage. So for the last few weeks andersca, xenon, and I have been cooking up an implementation!

The client-side database storage API allows web applications to store structured data locally using a medium many web developers are already familiar with – SQL.

The API is asynchronous and uses callback functions to track the results of a database query.

Compact usage defining a callback function on the fly might look something like this:

var database = openDatabase ( "Database Name" , "Database Version" ); database . executeSql ( "SELECT * FROM test" , function ( result1 ) { database . executeSql ( "DROP TABLE test" , function ( result2 ) { alert ( "My second database query finished executing!" ); }); });

There will also be a small example of how to use the API in a real site that we’ll try to keep up to date as things evolve.

This initial implementation has some things missing from the spec as well as a few known bugs. But it does the basics and the best way to discover what needs work is to get it out there for people to start using it!

If you find any bugs, would like to suggest features, or have gripes about the spec itself, please drop by #webkit or drop us a line on the WebKit email lists.

Oh, and one more thing…

We’re landing this initial implementation with pretty cool Web Inspector support!

So far you can view the full contents of any table and run arbitrary queries on each database a page is using. We have a lot of ideas for improvements but would also love to hear yours.