Using this form, you can import visitor statistics from your Google Analytics account(s). Once imported, the information is displayed in the upper-right corner for each feature table. Browser statistics are stored in your browser for future use.
The WCIU compatibility tables can be embedded through an iframe on your own website by appending "/embed" to any feature page's URL like this: http://caniuse.com/[feature id]/embed
For additional customization, use the following form:
Use at your own discretion, and please do not abuse. While the service should be pretty reliable, I make no guarantees for uptime, correctness, etc.
Related pages: HTML5 Demos, CSS3 Previews, HTML5 Feature detection.
Detailed tables: Web Designer's Checklist, Quirksmode
I use the following criteria:
I use a hand-crafted test suite to test features, which tests for basic support of each feature.
The test suite is publically available at tests.caniuse.com.
Most information comes directly from the latest developer/preview/nightly builds as seen in this list:
The "far past" is based roughly on the oldest version of a browser still in use. See for example YUI's graded browser support chart
The "future" eras are trickier, since it's not always obvious when a browser will be released. But in most cases you can make a pretty good guess.
When its primary purpose is largely fulfilled. It does not mean it's 100% supported, just that it's usable in most cases.
I try to keep it as current as possible, with new information being usually being processed within a few days. Follow the feed if you'd like keep up with all the changes made.
*Note that "Not ready" does not mean you can't start using it, it just means it won't work in all current selected browsers. Change the options to hide browsers you do not need to support.
*Global usage share statistics based on data from StatCounter GlobalStats for April, 2012. See the browser usage table for usage by browser version.