From WCAG 2.0 to MWBP: Making content that meets Web Content Accessibility Guidelines 2.0 also meet Mobile Web Best Practices

W3C Working Group Note 9 July 2009

Table of Contents


This page is part of a multi-page document. Please refer to the “How to Use This Document” section for more information.

For those familiar with Web Content Accessibility Guidelines 2.0, this page describes what also needs to be done to meet Mobile Web Best Practices (MWBP).

Summary of work required to make content that meets WCAG 2.0 also meet MWBP

Compliance with WCAG 2.0 helps go some way towards achieving compliance with some of the MWBP. This section provides a summary of these BPs. There are two possible levels of effort required, labelled for simplicity with the keywords nothing, something and everything. Note that coverage may depend on WCAG compliance level achieved and so a BP may appear in “something” and “nothing” lists (for example, LINK_TARGET_ID). To summarise, if your content already complies with WCAG 2.0, to achieve compliance with the MWBP, you need to do the following:

Nothing: If a provision is labelled “Nothing” then content that complies with WCAG 2.0 already complies with the provision and no further effort is necessary. The following list includes all of the provisions that are marked “Nothing”. Links in this section point to the relevant provisions.

Something: If a provision is labelled “Something” then more effort of some kind is necessary to comply with the provision. All of the provisions marked “Something” are included in the list below. Each item in the list is a link to an explanation of what is required, in the next section of this report. For each there is a list of the provisions that may provide some compliance or are in some way related. There is no direct correspondence between one provision and another. In some cases, it may be necessary to make an extra effort or to consider a more diverse range of user needs. In these cases, the word “possibly” is used. In other cases scope may be different, giving partial compliance. In these cases the word “partially” is used. BP links in this section point to the detail section below; SC links in this section point to WCAG 2.0.

Everything: For all other BPs, WCAG 2.0 does not ensure compliance and it will be necessary to do the work involved. These BPs are not related to any WCAG 2.0 success criteria.

Addressing Mobile Web Best Practices

This section lists each of the MWBPs that are related to WCAG 2.0 success criteria, which are listed under “something” above. For each BP, the section title is that of the BP. This is followed by a list of the SCs that can help meet it.

[BACKGROUND_IMAGE_READABILITY] When using background images make sure that content remains readable on the device

If overall contrast is sufficient, this goes part of the way to ensuring readability with background images.

[COLOR_CONTRAST] Ensure that foreground and background color combinations provide sufficient contrast

Unlike MWBP, WCAG specifies a contrast ratio and algorithm and certain types of content that are excluded from the requirement. The following SCs may ensure compliance with this BP. However, note that WCAG allows for exceptions for cases like large text, incidental text or images of text and logotypes. If content covered by the BP is not excluded, then compliance is ensured.

[CONTROL_LABELLING] Label all form controls appropriately and explicitly associate labels with form controls

The following SCs ensure compliance with this BP when using label elements to associate text labels with form controls (1.3.1 below), and either 3.3.2 or 4.1.2.

[CONTROL_POSITION] Position labels so they lay out properly in relation to the form controls they refer to

[GRAPHICS_FOR_SPACING] Do not use graphics for spacing

[MEASURES] Do not use pixel measures and do not use absolute units in markup language attribute values and style sheet property values

WCAG 2.0 does not prohibit the use of the pixel unit of measure.

[NAVIGATION] Provide consistent navigation mechanisms

[NON-TEXT_ALTERNATIVES] Provide a text equivalent for every non-text element

Note that the WAI Glossary definition of Non-text Content which is the basis for this BP, includes video and audio.

[PAGE_TITLE] Provide a short but descriptive page title

[POP_UPS] Do not cause pop-ups or other windows to appear and do not change the current window without informing the user

[REDIRECTION] Do not use markup to redirect pages automatically. Instead, configure the server to perform redirects by means of HTTP 3xx codes

The following SCs go some way to achieving compliance with this BP. Specifically, failure F41: Failure of Success Criterion 2.2.1, 2.2.4, and 3.2.5 due to using meta refresh with a time-out ensures compliance with this BP.

[STRUCTURE] Use features of the markup language to indicate logical document structure

The BP is less explicit about what structural elements to use, but the following SCs probably cover its intent.

[STYLE_SHEETS_SUPPORT] Organize documents so that if necessary they may be read without style sheets

[VALID_MARKUP] Create documents that validate to published formal grammars

Updated 27 June 2009.