Rationale

This document serves a rationale document for various parts of the HTML5 specification. Over time this page will be a complete rationale document.

Other Pages

• Why no namespaces
• Why no script implements
• Why not reuse legend or another mini-header element.
• Rationale for a variety of elements

Specific Elements

Plaintext

the <plaintext> element is a obsolete precursor to the <pre> element.^[1] It is is now in the HTML5 spec as a method of stopping all further html token parsing. It lacks an end tag and just emits the rest of the page as plain text. It throws a parse error upon reaching the end of the document as it is not considered a valid element (and it is missing an end-tag).

1. http://www.w3.org/MarkUp/draft-ietf-iiir-html-01.txt

Image

<image> element is treated as an alternate (but invalid) name for <img>. This is because some sites (around 0.2%) make this mistake. It is already treated as an image by most major browsers.

Meter and Progress (are not the same thing)

<meter> is not just a special case of <progress>. The progress element allows for indeterminate values and results in a completely different UI than the meter element.

A meter would be most appropriate for this kind of markup: <img src="http://developer.apple.com/mac/library/documentation/userexperience/conceptual/applehiguidelines/art/ct_leveldiscrete.gif" alt="example of proper rendering for the meter element">

The progress element on the other hand looks something like: <img src="http://developer.apple.com/mac/library/documentation/userexperience/conceptual/applehiguidelines/art/ct_determprogsizes.jpg"> An empty progress element could be used for: <img src="http://developer.apple.com/mac/library/documentation/userexperience/conceptual/applehiguidelines/art/ct_asynchprogindsizes.jpg" alt="picture of the default apple throbber">

See Re: <progress> draft for details.