The main part of Acid3 is written in ECMAScript (JavaScript) and consists of 100 subtests in six groups called "buckets", including four special subtests (0, 97, 98, and 99).

Bucket 1: DOM Traversal, DOM Range, HTTP
Bucket 2: DOM2 Core and DOM2 Events
Bucket 3: DOM2 Views, DOM2 Style, CSS 3 selectors and Media Queries
Bucket 4: Behavior of HTML tables and forms when manipulated by script and DOM2 HTML
Bucket 5: Tests from the Acid3 Competition (SVG, HTML, SMIL, Unicode, …)
Bucket 6: ECMAScript
The compliance criteria require that the test be run with a browser's default settings.
The final rendering must have a 100/100 score and must be pixel-identical with the reference rendering.
On browsers designed for personal computers, the animation has to be smooth (taking no more than 33 ms for each subtest on reference hardware equivalent to a top-of-the-line Apple laptop) as well, though slower performance on a slow device does not imply non-conformance.

To pass the test the browser must also display a generic favicon in the browser toolbar, not the favicon image from the Acid3 web server.
 The Acid3 server when asked for favicon.ico gives a 404 response code, but with image data in the body.
 This tests that the web browser correctly handles the 404 error code when fetching the favicon, by treating this as a failure and displaying the generic icon instead.

When the test is running, the rectangles will be added to the rendered image; the number of subtests passed in the bucket will determine the color of the rectangles.

0 subtests passed: No rectangle shown.

1–5 subtests passed: Black rectangle.

6–10 subtests passed: Grey rectangle.

11–15 subtests passed: Silver rectangle.

All 16 subtests passed: Colored rectangle (left to right: red, orange, yellow, lime, blue, purple).

Note that Acid3 does not display exactly how many subtests passed in a bucket.
For example, 3 subtests passing and 4 subtests passing in bucket 2 would both render a black rectangle.
The main part of Acid3 is written in ECMAScript (JavaScript) and consists of 100 subtests in six groups called "buckets", including four special subtests (0, 97, 98, and 99).
Bucket 1: DOM Traversal, DOM Range, HTTP
Bucket 2: DOM2 Core and DOM2 Events
Bucket 3: DOM2 Views, DOM2 Style, CSS 3 selectors and Media Queries
Bucket 4: Behavior of HTML tables and forms when manipulated by script and DOM2 HTML
Bucket 5: Tests from the Acid3 Competition (SVG, HTML, SMIL, Unicode, …)
Bucket 6: ECMAScript
The compliance criteria require that the test be run with a browser's default settings. The final rendering must have a 100/100 score and must be pixel-identical with the reference rendering. On browsers designed for personal computers, the animation has to be smooth (taking no more than 33 ms for each subtest on reference hardware equivalent to a top-of-the-line Apple laptop) as well, though slower performance on a slow device does not imply non-conformance.
To pass the test the browser must also display a generic favicon in the browser toolbar, not the favicon image from the Acid3 web server.  The Acid3 server when asked for favicon.ico gives a 404 response code, but with image data in the body.  This tests that the web browser correctly handles the 404 error code when fetching the favicon, by treating this as a failure and displaying the generic icon instead.
When the test is running, the rectangles will be added to the rendered image; the number of subtests passed in the bucket will determine the color of the rectangles.
0 subtests passed: No rectangle shown.
1–5 subtests passed: Black rectangle.
6–10 subtests passed: Grey rectangle.
11–15 subtests passed: Silver rectangle.
All 16 subtests passed: Colored rectangle (left to right: red, orange, yellow, lime, blue, purple).
Note that Acid3 does not display exactly how many subtests passed in a bucket. For example, 3 subtests passing and 4 subtests passing in bucket 2 would both render a black rectangle.
Acid3