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Gecko's "Almost Standards" Mode

As of Mozilla 1.0.1 and 1.1 beta, there is a new rendering mode referred to as "almost standards" mode. This is added to the long-standing "quirks" and "standards" modes.

"Almost standards" rendering mode is exactly the same as "standards" mode in all details save one: the layout of images inside table cells is handled as they are in Gecko's "quirks" mode, which is fairly consistent with other browsers, such as Internet Explorer. This means that sliced-images-in-tables layouts are less likely to fall apart in Gecko-based browsers based on the rendering engine found in Mozilla 1.0.1 or later when in either "quirks" or "almost standards" mode. (See the DevEdge article "Images, Tables, and Mysterious Gaps" for a detailed explanation of how such layouts are treated in "standards" mode.)

Other than this one difference, "almost standards" and "standards" modes are exactly the same in terms of layout and other behaviors.

Triggering "Almost Standards"

The DOCTYPEs that will trigger "almost standards" mode are those which contain:

A complete DOCTYPE contains a public identifier and a system identifier. In discussions of DOCTYPEs, many people will refer to a DOCTYPE as being "with URI" or "without URI." The URI is the system identifier. For example, consider the following DOCTYPE:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"
			"http://www.w3.org/TR/REC-html40/strict.dtd">

The parts are as follows:

Thus any HTML 4.01 Transitional or Frameset DOCTYPE with a URI (system identifier) will trigger "almost standards" mode, as will any XHTML 1.0 Transitional or Frameset DOCTYPE, with or without the URI. Authors outside of IBM do not need to worry about the custom DOCTYPE that will also trigger "almost standards" mode.

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