Acid2 is a test page for web browsers published by The Web Standards Project (WaSP). It has been written to help browser vendors make sure their products correctly support features that web designers would like to use. These features are part of existing standards but haven’t been interoperably supported by major browsers. Acid2 tries to change this by challenging browsers to render Acid2 correctly before shipping.

Acid2 is a complex web page. It uses features that are not in common use yet, because of lack of support, and it crams many tests into one page. The aim has been to make it simple for developers and users to check if a browser passes the test.

After passing Acid2 test, a browser should allow the following:

• Transparent PNGs - The eyes are encoded as transparent PNGs.
• The object element - The eyes of the face are attached to an object element. Being able to use object (which can have alternative content) is one of the oldest requests from web designers.
• Absolute, relative and fixed positioning - Being able to position elements accurately is important for advanced page layouts.
• Box model - The original Acid test focused on the CSS box model. Acid2 continues in this fine tradition by testing ‘height’, ‘width’, ‘max-width’, ‘min-width’, ‘max-height’ and ‘min-height’.
• CSS tables - There is nothing wrong with table layouts. It is a powerful layout model which makes sense on bigger screens. However, the table markup is troublesome as it ties the content to these screens. Therefore, being able to specify table layouts in CSS is important.
• Margins - CSS defines accurate algorithms for how margins around elements should be calculated.
• Generated content - The ability to add decorations and annotations to Web pages without modifying the markup has long been requested by authors.
• CSS parsing - Acid2 includes a number of illegal CSS statements that should be ignored by a compliant browser.
• Paint order - We test that overlapping content is painted in the right order. This is not a feature in itself, but a requirement for other features to work correctly.
• Line heights - The Acid2 test checks a few key parts of the CSS inline box model, upon which any standards-compliant Web page depends.
• Hovering effects - One of the elements in the face changes color when you hover over it. Which one?

Read More...