Techniques for WCAG 2.0

This describes the failure condition that results when CSS, rather than structural markup, is used to modify the visual layout of the content, and the modified layout changes the meaning of the content. Using the positioning properties of CSS2, content may be displayed at any position on the user's viewport. The order in which items appear on a screen may be different than the order they are found in the source document. Assistive technologies rely on the source code or other programmatically determined order to render the content in the correct sequence. Thus, it is important not to rely on CSS to visually position content in a specific sequence if this sequence results in a meaning that is different from the programmatically determined reading order. [LC-600]

No resources available for this technique.

• C6: Positioning content based on structural markup

Procedure

For content which uses CSS for positioning:

1. Remove the style information from the document or turn off use of style sheets in the user agent.

2. Check that the reading order of the content is correct and the meaning of the content is preserved.

Expected Results

• If step #2 is false, then this failure condition applies and the content fails this success criterion.

It is a failure to use CSS to style text to convey information instead of conveying the information by using the appropriate markup or text. An HTML example is to use CSS to style text in bold for emphasis rather than using the strong element.

No resources available for this technique.

• H49: Using semantic markup to mark emphasized or special text

Procedure

1. Find visually styled elements on the page that convey information.

2. Check that the appropriate semantics of the technology are used and that the information is not conveyed only by variations in presentation through CSS.

Expected Results

• If step #2 is false, then this failure condition applies and the content fails this success criterion.

The CSS background-image property provides a way to include images in the document with CSS without any reference in the HTML code. The CSS background-image property was designed for decorative purposes and it is not possible to associate text alternatives with images that are included via CSS. Text alternatives are necessary for people who cannot see images that convey important information. Therefore, it is a failure to use this property to add images to convey important information.

No resources available for this technique.

• H37: Using alt attributes on img elements

Procedure

1. Examine all images added to the content via CSS.

2. Check that the images do not convey important information.

Expected Results

• Step #2. If it is true then this failure condition applies and content fails the success criterion.

CSS defines the blink value for the text-decoration property. When used, it causes any text in elements with this property to blink at a predetermined rate. This cannot be interrupted by the user, nor can it be disabled as a user agent preference. The blinking continues as long as the page is displayed. Therefore, content that uses text-decoration:blink fails the success criterion because blinking can continue for more than three seconds.

Resources are for information purposes only, no endorsement implied.

• CSS 2 text-decoration property

• SCR22: Using scripts to control blinking and stop it in three seconds or less

Procedure

1. Examine inline styles, internal stylesheets, and external stylesheets for the text-decoration property with a value of "blink".

2. If the property is used, determine if the ID, class, or element identified by selectors on which this property is defined are used in the document.

Expected Results

• If step #1 and step #2 are true, the content fails the success criterion.

When content that is rendered by a plug-in or contained in an applet blinks, there may be no way for the user agent to pause the blinking. If neither the plug-in, applet, nor the content itself provides a mechanism to pause the content, the user may not have sufficient time to read the content between blinks or it may be so distracting that the user will not be able to read other content on the page.

• SCR22: Using scripts to control blinking and stop it in three seconds or less

Procedure

For each page that has blinking content in a plugin or applet:

1. Determine if the content continues to blink for longer than 3 seconds.

2. Determine if there is a means to pause the blinking content.

Expected Results

• If step #1 is true and step #2 is false, the content fails the success criterion.

This describes a failure condition for all techniques involving captions. If the "caption" does not include all of the dialog (either verbatim or in essence) as well as all important sounds then the 'Captions' are not real captions.

NOTE: Captions sometimes simplify the spoken text both to make it easier to read and to avoid forcing the viewer to read at very high speed. This is standard procedure and does not invalidate a caption.

No resources available for this technique.

(none currently listed)

Procedure

1. View the material with captioning turned on.

2. Check that all dialog is accompanied by a caption.

3. Check that all important sounds are captioned.

Expected Results

• Step #2 and step #3 are true.

This document describes a failure that occurs when removing focus from a form element, such as by moving to the next element, causes a change of context.

Resources are for information purposes only, no endorsement implied.

• F37: Failure of SC 3.2.2 due to launching a new window without prior warning when the status of a radio button, check box or select list is changed
• F60: Failure of SC 3.2.5 due to launching a new window when a user enters text into an input field

Procedure

1. Find all form elements.

2. Go through them in order.

3. Check if the form submits when you move from one field to the next.

4. Check if moving from one field to the next launches any new windows.

5. Check if moving from one filed to the next navigates to another screen.

Expected Results

• If step #3, step #4, or step #5 is true, then this failure condition applies and the content fails the success criterion.

When content includes multiple formats, one or more user agents or plug-ins are often needed in order to successfully present the content to users. For example, a page that includes (X)HTML, SVG, SMIL and XForms may require a browser to load as many as three different plug-ins in order for a user to successfully interact with the content. Some plug-ins create a common situation in which the keyboard focus can become "stuck" in inaccessible plug-ins, leaving a keyboard-only user with no way to return to the accessible content.

No resources available for this technique.

• G21: Ensuring that users are not trapped in content
• SCR20: Using both keyboard and other device-specific functions

Procedure

1. Using a keyboard, navigate through the content.

2. Check to see that the keyboard focus is not "trapped" and it is possible to move keyboard focus out of the plug-in content without closing the user agent or restarting the system.

Expected Results

• If the keyboard focus becomes "trapped," then this failure condition applies and content fails the success criterion and conformance requirement.

Web servers that require user authentication usually have a session mechanism in which a session times out after a period of inactivity from the user. This is sometimes done for security reasons, to protect users who are assumed to have left their computer exposed in a state where someone could do something harmful to them such as transfer bank funds or make an unauthorized purchase. A user with a disability may actually still be working to complete the form as it may take him or her longer to complete the form than would normally be expected. Upon re-authentication, if the state of the user's session is not restored, including all data that had been previously entered into the form, he or she will have to start over. And for these users, it is likely that the session will time out again before they can complete the form. This sets up a situation where a user who needs more time to complete the form can never complete it.

• G105: Saving data so that it can be used after a user re-authenticates

Procedure

On a site where authentication is required, user input is collected, and which ends the user's session after a known period of inactivity:

1. Provide user input as required but allow the session to time out, then submit the form.

2. When requested, re-authenticate with the server.

3. Determine if the function is performed using the previously submitted data.

Expected Results

• If step #3 is false, the site fails the success criterion.

This objective of this technique is to describe the failure that occurs when an image uses color to convey information, but the text alternative for the image does not convey that information. This can cause problems for people who are blind or colorblind because they will not be able to perceive the information conveyed by the color.

No resources available for this technique.

• G94: Providing short text alternative for non-text content that serves the same purpose and presents the same information as the non-text content

Procedure

For all images in the content that convey information by way of color :

1. Check that the information conveyed by color is not included in the text alternative for the image.

Expected Results

• If step #1 is true, then this failure condition applies and content fails the success criterion.

The objective of this technique is to show how identifying content only by its shape or location makes content difficult to understand and operate. When only visual identification or location is used, users with visual disabilities may find it difficult to locate content since they cannot see the screen or may perceive only a small portion of the screen at one time. Also, location of content can vary if page layout varies due to variations in font, window, or screen size.

No resources available for this technique.

• G96: Providing textual identification of items that otherwise rely only on shape and/or position to be understood

Procedure

1. Examine the Web page for textual references to content within the Web page.

2. Check that the references do not rely on only the shape or location of the content.

Expected Results

• If step #2 is false, then this failure condition applies and the content fails this success criterion.

When standard controls from accessible technologies are used, they usually are programmed in a way that uses and supports the accessibility API. If custom controls are created, however, then it is up to the programmer to be sure that the newly created control supports the accessibility API. If this is not done, then assistive technologies will not be able to understand what the control is or how to operate it or may not even know of its existence.

Resources are for information purposes only, no endorsement implied.

• Active Accessibility Checker (AccExplorer)

• JAVA Accessibility Helper

(none currently listed)

Procedure

1. Using the accessibility checker for the technology (or if that is not available, inspect the code or test with an assistive technology), check the controls to see if they support the accessibility API.

Expected Results

• If step #1 is false, then this failure condition applies and the content fails this success criterion

In this failure technique, there is moving or scrolling content that cannot be paused and resumed by users. In this case, some users with low vision or cognitive disabilities will not be able to perceive the content.

• G4: Allowing the content to be paused and restarted from where it was stopped

Procedure

On a page with moving or scrolling content,

1. Check that a mechanism is provided in the Web page or user agent to pause moving or scrolling content.

2. Use the pause mechanism to pause the moving or scrolling content.

3. Check that the moving or scrolling has stopped and does not restart by itself.

4. Check that a mechanism is provided in the Web page or user agent to restart the paused content.

5. Use the restart mechanism provided to restart the moving content.

6. Check that the movement or scrolling has resumed from the point where it was stopped.

Expected Results

• If steps step #1, step #3, step #4, or step #6 are false, then the content fails the success criterion.

The objective of this technique is to ensure that Web pages can be interpreted consistently by user agents, including assistive technology. If it is ambiguous, different user agents including assistive technologies could present different information to their users. Users of assistive technology for example may have different information presented to them than users of other mainstream user agents. Some elements and attributes in markup languages are required to have unique values, and if this requirement is not honored, the result can be irregular or not uniquely resolvable content. For example, when id attribute values are not unique, they are particularly problematic when referenced by labels, headers in data tables, or used as fragment identifiers, as user agents do not have enough information to provide determine essential relationships (i.e. to determine which label goes with which item).

No resources available for this technique.

(none currently listed)

Procedure

1. Check for id and accesskey values which are not unique within the document.

2. Check that attribute values that have an idref value have a corresponding id value.

3. For tables that use the axis attribute, check that all values listed in the axis attribute have a corresponding id value in a table header cell in the same table.

4. For client-side image maps, check that the value of the usemap attribute has a corresponding id value if the usemap attribute is not a URL.

Expected Results

• If step #1, step #3 or step #4 is true or step #2 is false, then this failure condition applies and the content fails the success criterion.

This failure technique describes the situation in which an alternate, conforming version of the content is provided, but there is no direct way for a user to tell that it is available or where to find it. Such content fails the success criterion because the user cannot find the conforming version.

• G136: Providing a link at the beginning of the nonconforming content that points to an alternate version that does meet WCAG 2.0 at the level claimed

Procedure

1. Identify a nonconforming page that has an alternative conforming version.

2. Determine if the nonconforming page provides a link to the conforming version.

Expected Results

1. If step #2 is false, the content fails the success criterion.

The objective of this failure condition is to address situations where the non-text content is updated, but the text alternative is not updated at the same time. If the text in the text alternative can not still be used in place of the non-text content without losing information or function, then it fails because it is no longer a text alternative for the non-text content.

No resources available for this technique.

(none currently listed)

Procedure

1. Check each text alternative to see if it is describing content other than the currently-displayed non-text content.

Expected Results

• If step #1 is true then the text alternative is not up to date with current item, this failure condition applies, and content fails these success criteria.

Failure due to opening new windows when the user does not expect them. New windows take the focus away from what the user is reading or doing. This is fine when the user has interacted with a piece of User Interface and expects to get a new window, such as an options dialog. The failure comes when pop-ups appear unexpectedly.

No resources available for this technique.

• SCR24: Using script to open a new window on user request

Procedure

1. Load the Web page.

2. Check if new (additional) windows open.

3. Find every actionable element, such as links and buttons, in the Web page.

4. Activate each element.

5. Check if activating the element opens a new window.

6. Check if elements that open new windows have associated text saying that will happen. The text can be displayed in the link, or available through a hidden association such as an HTML title attribute.

Expected Results

• If step #2 is true, the failure condition applies and the content fails the success criterion

• If step #5 is true and step #6 is false, the failure condition applies and the content fails the success criterion

This describes a failure condition for SC involving sound. If sound does not turn off automatically within 3 seconds and there is no way to turn the sound off then SC 1.4.2 would not be met. Sounds that play over 3 seconds when there is no mechanism to turn off the sound included in the content would fall within this failure condition.

No resources available for this technique.

(none currently listed)

Procedure

1. Check that there is a way in content to turn off any sound that plays automatically for more than three seconds.

Expected Results

• If step #1 is not true then content fails Success Criterion 1.4.2

Users with vision loss or cognitive challenges often require specific foreground and background color combinations. For instance, many people with low vision find it much easier to see a Web page that has white text on a black background, so they may have set their user agent to create this contrast. If the author specifies that the text must be black, then it may override the settings of the user agent and render a page that has black text (specified by the author) on black background (that was set in the user agent). This principle also works in reverse. If the Webmaster forces the background to be white, then the white background specified by the author would be the same color as the white text (which was set in the user agent) rendering the page unusable to the user. Therefore, if the author specifies a foreground text color then they should also specify a background color which has sufficient contrast (link) with the foreground and vice versa.

Resources are for information purposes only, no endorsement implied.

• Assigning property values, Cascading, and Inheritance [LC-767]

(none currently listed)

Procedure

1. Examine the code of the Web page.

2. Check to see if a foreground color is specified

3. Check to see if a background color is specified

Expected Results

If step #2 is true but step #3 is false, OR if step #3 is true but step #2 is false then this failure condition applies and content fails these success criteria.

This describes a failure condition when the Web page has a title, but the title does not identify the contents or purpose of the Web page.

No resources available for this technique.

• H25: Providing a title using the title element

Procedure

1. Check whether the title of each Web page identifies the contents or purpose of the Web page .

Expected Results

• If step #1 is false, then this failure condition applies and the content fails this success criterion.

The objective of this technique is to show how using a graphical symbol to convey information can make content difficult to comprehend. A graphical symbol may be an image, an image of text or a pictorial or decorative character symbol (glyph) which imparts information nonverbally. Examples of graphical symbols include an image of a red circle with a line through it, a "smiley" face, or a glyph which represents a check mark, arrow, or other symbol but is not the character with that meaning. Assistive technology users may have difficulty determining the meaning of the graphical symbol. If a graphical symbol is used to convey information, provide an alternative using features of the technology or use a different mechanism that can be marked with an alternative to represent the graphical symbol. For example, an image with a text alternative can be used instead of the glyph. [LC-780]

No resources available for this technique.

• H37: Using alt attributes on img elements

Procedure

1. Examine the page for non-text marks that convey information.

2. Check whether there are other means to determine the information conveyed by the non-text marks.

Expected Results

• If step #2 is false, then this failure condition applies and the content fails this success criterion.

This describes a failure condition for all techniques involving text alternatives. If the text in the "text alternative" cannot be used in place of the non-text content without losing information or function then it fails because it is not, in fact, an alternative to the non-text content.

No resources available for this technique.

(none currently listed)

Procedure

1. Check each text alternative to see if it is not actually a text alternative for the non-text content.

Expected Results

• If step #1 is true then this failure condition applies and content fails the success criterion.

Components that have the same function in different Web pages are more easily recognized if they are labeled consistently. If the naming is not consistent, some users may get confused.

No resources available for this technique.

(none currently listed)

Procedure

1. In a set of Web pages, find components with the same function that are repeated in multiple Web pages.

2. For each component with the same function found in step #1, check that the naming is consistent.

Expected Results

If step #2 is false then this failure condition applies and content fails the success criterion.

The objective of this technique is to describe how using white space characters, such as space, tab, line break, or carriage return, to format individual words visually can be a failure to present meaningful sequences properly. When blank characters are inserted to control letter spacing within a word, they may change the interpretation of the word or cause it not to be programmatically recognized as a single word. [LC-781]

Inserting white space characters into an initialism is not an example of this failure, since the white space does not change the interpretation of the initialism and may make it easier to understand.

The use of white space between words for visual formatting is not a failure, since it does not change the interpretation of the words.

No resources available for this technique.

• C8: Using CSS letter-spacing to control spacing within a word

Procedure

For each word that appears to have non-standard spacing between characters:

1. Check whether any words in the text of the content contain white space characters .

Expected Results

• If step #1 is true, then this failure condition applies and the content fails this success criterion.

The objective of this technique is to describe how using white space characters, such as space, tab, line break, or carriage return, to format columns of data in text content is a failure to use structure properly. Assistive technologies will interpret content in the reading order of the current language. Using white space characters to create multiple columns does not provide the information in a natural reading order. Thus, the assistive technology user will not be presented with the information in an understandable manner.

Plain text is not suitable for displaying multiple columns of text. Modify the content to present the data in a different layout. Alternatively, use a technology that provides structural elements to represent columnar data.

No resources available for this technique.

(none currently listed)

Procedure

1. Examine the document for data or information presented in columnar format.

2. Check whether the columns are created using white space characters to lay out the information.

Expected Results

• If step #2 is true, then this failure condition applies and the content fails these success criteria.

The objective of this technique is to describe how using white space characters, such as space, tab, line break, or carriage return, to format tables in text content is a failure to use structure properly. When tables are created in this manner there is no way to indicate that a cell is intended to be a header cell, no way to associate the table header cells with the table data cells, or to navigate directly to a particular cell in a table.

In addition, assistive technologies will interpret content in the reading order of the current language. Using white space to organize data in a visual table does not provide the information in a natural reading order in the source of the document. Thus, the assistive technology user will not be presented with the information in a logical reading order.

Plain text is not suitable for displaying complex information like tables because the structure of the table cannot be perceived. Rather than using visual formatting to represent tabular relations, tabular information would need to be presented using a different technology or presented linearly. (See Presenting tabular information in plain text) [LC-672]

No resources available for this technique.

• H51: Using table markup to present tabular information

Procedure

1. Examine the document for visually formatted tables.

2. Check whether the tables are created using white space characters to layout the tabular data.

Expected Results

• If step #2 is true, then this failure condition applies and the content fails these success criteria.

Forms are frequently designed so that they submit automatically when the user has filled in all the fields, or when focus leaves the last field. There are two problems with this approach. First is that a disabled user who needs more context may move focus away from the field to the directions on how to fill in the form, or to other text, accidentally submitting the form. The other is that, with some form elements, the value of the field changes as each item is navigated with the keyboard, again accidentally submitting the form. It is better to rely on the standard form behavior of the submit button and enter key.

Resources are for information purposes only, no endorsement implied.

Procedure

1. Enter data in all fields on page starting at top.

2. Enter data in last field and exit from it (tab out of it).

3. Check whether leaving the last field causes change of context.

Expected Results

• If step #3 is true, then this failure condition applies and content fails the success criterion.

This document describes a failure that occurs when changing the status of a radio button, a check box or an item in a select list causes a new window to open. It is possible to use scripting to create an input element that causes a change of context (submit the form, open a new page, a new window) when the element is selected. Developers can instead use a submit button (see G80: Providing a submit button to initiate a change of context) or clearly indicate the expected action.

No resources available for this technique.

(none currently listed)

Procedure

1. Find each form in a page.

2. For each form control that is a radio button, check box or an item in a select list, check if changing the status of the control launches a new window.

3. For each new window resulting from step 2, check if the user is warned in advance.

Expected Results

If step #3 is false, then this failure condition applies and content fails the success criterion.

This describes a failure condition for text alternatives for images that should be ignored by AT. If there is no alt attribute at all assistive technologies are not able to ignore the non-text content. The alt attribute must be proved and have a null value (i.e. alt="" or alt=" ") to avoid a failure of this success criterion.

No resources available for this technique.

(none currently listed)

Procedure

1. Identify any img and applet elements that are used for purely decorative content;

2. Check that the alt attribute for these elements exists.

3. Check that the alt attribute for these elements is null.

Expected Results

• if step #2 or step #3 is false, this failure condition applies and content fails the success criterion.

This describes a failure condition for text alternatives for images that should be ignored by AT. If there is no alt attribute at all assistive technologies are not able to ignore the non-text content. The alt attribute must be proved and have a null value (i.e. alt="" or alt=" ") to avoid a failure of this success criterion.

Note: Although alt=" " is valid, alt="" is recommended.

No resources available for this technique.

(none currently listed)

Procedure

1. Identify any img and applet elements that are used for purely decorative content;

2. Check that the alt attribute for these elements exists.

3. Check that the alt attribute for these elements is null.

Expected Results

• If step #2 or step #3 is false, this failure condition applies and content fails the success criterion.

meta http-equiv of {time-out}; url=... is often used to automatically redirect users. When this occurs after a time delay, it is an unexpected change of context that may interrupt the user.

It is acceptable to use the meta element to create a redirect when the time-out is set to zero, since the redirect is instant and will not be perceived as a change of context. However, it is preferable to use server-side methods to accomplish this. See SVR1: Implementing automatic redirects on the server side instead of on the client side (SERVER) .

Resources are for information purposes only, no endorsement implied.

• HTML 4.01 META element

Procedure

1. View a page.

2. Check that the page does not redirect after a time-out.

Expected Results

1. #2 is true.

meta http-equiv of refresh is often used to periodically refresh pages or to redirect users to another page. If the time interval is too short, people who are blind will not have enough time to make their screen readers read the page before the page refreshes unexpectedly and causes the screen reader to begin reading at the top. Sighted users may also be disoriented by the unexpected refresh.

• SVR1: Implementing automatic redirects on the server side instead of on the client side

Procedure

1. Find meta elements in the document.

2. For each meta element, check if it contains the attribute http-equiv with value "refresh" (case-insensitive) and the content attribute with a number (representing seconds) greater than 0.

Expected Results

• If step 2 is true then this failure condition applies and content fails these success criteria.

This failure occurs when JavaScript event handlers are attached to elements to ''emulate links''. If scripting events are used to emulate links, user agents including assistive technology may not be able to identify the links in the content as links. They may not be recognized as interactive controls by assistive technology, or they may be recognized as interactive controls but still not recognized as links. Such elements do not appear in the links list generated by user agents or assistive technology.

The <a href> and <area> elements are intended to mark up links.

Attaching event handlers to elements that are not normally interactive, such as span and div, can be quite disorienting to users. Even if care is taken to provide keyboard access to such elements, users may have a difficult time discovering that there are interactive controls in the content or understanding what type of behavior to expect from them. For example, users may not know which keystrokes are supported by the script to activate the element. Additionally, these elements do not generate the same operating system events as interactive elements, so assistive technology may not be notified when the user activates them.

No resources available for this technique.

• G115: Using semantic elements to mark up structure

Procedure

1. Check whether there are JavaScript event handlers on an element that emulates a link.

2. Check whether the programmatically determined role of the element is link.

Expected Results

• If check #1 is true and check #2 is false, then this failure condition applies and content fails the success criterion.

The objective of this technique is to describe a failure that occurs when structural markup is used to achieve a presentational effect, but indicates relationships that do not exist in the content. This is disorienting to users who are depending on those relationships to navigate the content or to understand the relationship of one piece of the content to another. Note that the use of HTML tables for layout is not an example of this failure as long as the layout table does not include improper structural markup such as <th> or <caption> elements.

No resources available for this technique.

• F46: Failure of SC 1.3.1 due to using th elements, caption elements, or non-empty summary attributes in layout tables
• G115: Using semantic elements to mark up structure
• H39: Using caption elements to associate data table captions with data tables
• H42: Using h1-h6 to identify headings
• H73: Using the summary attribute of the table element to give an overview of data tables

Procedure

1. Check that each element's semantic meaning is appropriate for the content of the element.

Expected Results

• If check #1 is false, then this failure condition applies and the content fails the success criterion.

This document describes a failure that occurs when the tab order does not follow logical relationships and sequences in the content.

Focusable elements like links and form elements have a tabindex attribute. The elements receive focus in ascending order of the value of the tabindex attribute. When the values of the tabindex attribute are assigned in a different order than the relationships and sequences in the content, the tab order no longer follows the relationships and sequences in the content.

One of the most common causes of this failure occurs when editing a page where tabindex has been used. It is easy for the tab order and the content order to fall out of correspondence when the content is edited but the tabindex attributes are not updated to reflect the changes to the content.

Resources are for information purposes only, no endorsement implied.

• HTML 4.01 Tabbing navigation

• H4: Creating a logical tab order through links, form controls, and objects

Procedure

1. If tabindex is used, check that the tab order specified by the tabindex attributes follows relationships in the content.

Expected Results

• If check #1 is false, then this failure condition applies and content fails the success criterion.

The objective of this technique is to describe a failure that occurs when a table used only for layout includes either th elements, a summary attribute, or a caption element. This is a failure because it uses structural (or semantic) markup only for presentation. The intent of the HTML table element is to present data.

Although not commonly used in a layout table, the following structural markup would also be failures of Success Criterion 1.3.1 if used in a layout table:

• headers attributes

• scope attributes [LC-679]

Assistive technologies use the structure of an HTML table to present data to the user in a logical manner. The th element is used to mark the column and row headers of the table. A screen reader uses the information in th elements to speak the header information that changes as the user navigates the table. The summary attribute on the table element provides a textual description of the table that describes its purpose and function. Assistive technologies make the summary attribute information available to users. The caption element is part of the table and identifies the table.

Although WCAG 2 does not prohibit the use of layout tables, CSS-based layouts are recommended in order to retain the defined semantic meaning of the HTML table elements and to conform to the coding practice of separating presentation from content. [LC-1407] When a table is used for layout purposes the th element should not be used. Since the table is not presenting data there is no need to mark any cells as column or row headers. Likewise, there is no need for an additional description of a table which is only used to layout content. Do not include a summary attribute and do not use the summary attribute to describe the table as, for instance, "layout table". When spoken, this information does not provide value and will only distract users navigating the content via a screen reader. Empty summary attributes are acceptable on layout tables, but not recommended.

No resources available for this technique.

• H39: Using caption elements to associate data table captions with data tables
• H51: Using table markup to present tabular information
• H73: Using the summary attribute of the table element to give an overview of data tables

Procedure

1. Examine the source code of the HTML document for the table element

2. If the table is used only to visually lay out elements within the content

   1. Check that the table does not contain any th elements.

   2. Check that the table element does not contain a non-empty summary attribute.

   3. Check that the table element does not contain a caption element.

Expected Results

• If any check above is false, then this failure condition applies and the content fails the success criterion.

The blink element, while not part of the official HTML specification, is supported by many user agents. It causes any text inside the element to blink at a predetermined rate. This cannot be interrupted by the user, nor can it be disabled as a preference. The blinking continues as long as the page is displayed. Therefore, content that uses blink fails the success criterion because blinking can continue for more than three seconds.

Procedure

1. Examine code for the presence of the blink element.

Expected Results

• If #1 is true, the content fails the success criterion.

This document describes a failure caused by use of the HTML pre element to markup tabular information. The pre element preserves only visual formatting. If the pre element is used to markup tabular information, the visually implied logical relationships between the table cells and the headers are lost if the user cannot see the screen or if the visual presentation changes significantly.

Instead, the HTML table element is intended to present tabular data. Assistive technologies use the structure of an HTML table to present data to the user in a logical manner. This structure is not available when using the pre element.

No resources available for this technique.

• H51: Using table markup to present tabular information

Procedure

1. Check to see if the pre element is used

2. For each occurrence of the pre element, check whether the enclosed information is tabular.

Expected Results

• If check #2 is true, then this failure condition applies and the content fails the success criterion.

Although WCAG 2 does not prohibit the use of layout tables, CSS-based layouts are recommended in order to retain the defined semantic meaning of the HTML table elements and to conform to the coding practice of separating presentation from content. If a layout table is used, however, it is important that the content make sense when linearized. [LC-1407]

This failure occurs when a meaningful sequence of content conveyed through presentation is lost because HTML tables used to control the visual placement of the content do not “linearize” correctly. Tables present content in two visual dimensions, horizontal and vertical. However, screen readers present this two-dimensional content in linear order of the content in the source, beginning with the first cell in the first row and ending with the last cell in the last row. The screen reader reads the table from top to bottom, reading the entire contents of each row before moving to the next row. The complete content of each cell in each row is spoken—including the complete content of any table nested within a cell. This is called linearization.

Suppose that a Web page is laid out using a table with 9 columns and 22 rows. The screen reader speaks the content of the cell at Column 1, Row 1 followed by the cells in columns 2, 3, 4 and so on to column 9. However, if any cell contains a nested table, the screen reader will read the entire nested table before it reads the next cell in the original (outer) table. For example, if the cell at column 3, row 6 contains a table with 6 columns and 5 rows, all of those cells will be read before Column 4, Row 6 of the original (outer) table. As a result, the meaningful sequence conveyed through visual presentation may not be perceivable when the content is spoken by a screen reader.

No resources available for this technique.

• C6: Positioning content based on structural markup

Procedure

1. Linearize the content in either of the following ways:

   • Present the content in source code order

   • Remove the table markup from around the content

2. Check that the linear reading order matches any meaningful sequence conveyed through presentation.

Expected Results

• If check #2 is false, then this failure condition applies and the content fails this success criterion.

Scripts can be used to blink content by toggling the content's visibility on and off at regular intervals. It is a failure for the script not to include a mechanism to stop the blinking at 3 seconds or earlier. See SCR22: Using scripts to control blinking and stop it in three seconds or less (SCRIPT) for information about how to modify the technique to stop the blinking.

• SCR22: Using scripts to control blinking and stop it in three seconds or less

Procedure

For each instance of blinking content:

1. Determine if the blinking stops in 3 seconds or less.

Expected Results

If #1 is false, then the content fails the success criterion.

Some Web sites open a new window when a page is loaded, to advertise a product or service. The objective of this technique is to ensure that pages do not disorient users by opening up one or more new windows as soon as a page is loaded. Unless instructions that describe the behavior are provided before the request to open the new page is made, opening a new window as soon as a new page is loaded is a failure condition for this success criterion.

Resources are for information purposes only, no endorsement implied.

• G107: Using "activate" rather than "focus" as a trigger for changes of context

Procedure

1. load a new page

2. check to see whether a new window has been opened as a result of loading the new page

Expected Results

• If step 2 is true, then this failure condition applies and content fails the success criterion.

When pointing device-specific event handlers are the only mechanism available to invoke a function of the content, users with no vision (who cannot use devices such as mice that require eye-hand coordination) as well as users who must use alternate keyboards or input devices that act as keyboard emulators will be unable to access the function of the content.

Resources are for information purposes only, no endorsement implied.

• SCR20: Using both keyboard and other device-specific functions

Procedure

1. Check to see whether pointing-device-specific event handlers are the only means to invoke scripting functions.

Expected Results

• If any are found, then this failure condition applies and content fails the success criterion.

Content that normally receives focus when the content is accessed by keyboard may have this focus removed by scripting. While this is done to remove an undesired visual focus indicator, it removes the keyboard focus completely. This typically means the content can only be accessed by a pointer device, such as a mouse.

No resources available for this technique.

(none currently listed)

Procedure

1. Use the keyboard to verify that you can get to all interactive elements using the keyboard.

2. Check that when focus is placed on each element, focus remains there until user moves it.

Expected Results

• If #2 is false then this failure condition applies and content fails the success criterion.

Server-side scripting languages allow developers to set the non-standard HTTP header "Refresh" with a time-out (in seconds) and a URL to which the browser is redirected after the specified time-out. If the time interval is too short, people who are blind will not have enough time to make their screen readers read the page before the page refreshes unexpectedly and causes the screen reader to begin reading at the top. Sighted users may also be disoriented by the unexpected refresh.

The HTTP header that is set is Refresh: {time in seconds}; url={URI of new location}. It is also possible to omit the URL and obtain a periodically refreshing page, which causes the same problem. The HTTP header that is set is Refresh: {time in seconds}.

Resources are for information purposes only, no endorsement implied.

• Hypertext Transfer Protocol -- HTTP/1.0 (IETF Request for Comments 1945) (plain text)

• Hypertext Transfer Protocol -- HTTP/1.1 (IETF Request for Comments 2616) (plain text)

• An Exploration of Dynamic Documents by Netscape describes the nonstandard Refresh header that was introduced with Netscape Navigator 1.1.

• F40: Failure of SC 2.2.1 due to using meta redirect with a time limit
• F41: Failure of SC 2.2.1, 2.2.5, and 3.2.5 due to using meta refresh with a time-out

Procedure

1. When a Web page is rendered, check to see if it automatically redirects to another page after some period of time without the user taking any action.

Expected Results

• If such a redirect is found then this failure condition applies and content fails the success criterion.

This failure demonstrates how using generic HTML elements to create user interface controls can make the controls inaccessible to assistive technology. Assistive technologies rely on knowledge of the role and current state of a component in order to provide that information to the user. Many HTML elements have well defined roles, such as links, buttons, text fields, etc. Generic elements such as div and span do not have any predefined roles. When these generic elements are used to create user interface controls in HTML the assistive technology may not have the necessary information to describe and interact with the control.

See the resources section below for links to specifications which describe mechanisms to provide the necessary role and state information to create fully accessible user interface controls.

Resources are for information purposes only, no endorsement implied.

• Dynamic Accessible Web Content Roadmap

• Accessible DHTML

• F42: Failure of SC 1.3.1 due to using scripting events to emulate links

Procedure

1. Examine the source code for elements which have event handlers assigned within the markup or via scripting.

2. If those elements are acting as user interface controls, check that the role of the control is defined.

Expected Results

If check #2 is false and the created user interface control does not have role information, this failure condition applies.

This document describes a failure that occurs when a new window is created in response to a user filling in a text field for other than error reporting.

Resources are for information purposes only, no endorsement implied.

• F37: Failure of SC 3.2.2 due to launching a new window without prior warning when the status of a radio button, check box or select list is changed

Procedure

1. Find all text input form fields

2. Change the value in each form field

3. Check if new windows open

4. For any new windows that open, check if they contain an error message and a button that closes the window returning focus to the initiating form element.

Expected Results

• If #3 is true and #4 is false then failure condition applies and the content fails this success criterion.

This document describes a failure that occurs when the content filling the user's entire viewport is automatically updated, and the content does not contain options for disabling this behavior.

Resources are for information purposes only, no endorsement implied.

(none currently listed)

Procedure

1. open the content

2. leave the content open for 24 hours

3. check if the content changed

4. check if there are settings within the content to disable automatic changes

Expected Results

1. If both 3 and 4 are true, then this failure condition applies and the content fails this success criterion.

The objective of this technique is to ensure that Web pages can be interpreted consistently by user agents, including assistive technology. If specific relationships in a Web page are ambiguous, different user agents, including assistive technologies, could present different information to their users. Users of assistive technology, for example, may have different information presented to them than users of other mainstream user agents. Some elements and attributes in markup languages are required to have unique values, and if this requirement is not honored, the result can be irregular or not uniquely resolvable content.

Resources are for information purposes only, no endorsement implied.

(none currently listed)

Procedure

1. Check that all id values within the document (as defined by the schema) are unique.

2. Check that elements or attributes that refer to unique identifiers inside the same document have a corresponding id value.

Note that for XML document types defined by a DTD, this refers to attributes of type ID, IDREF or IDREFS. For XML document types defined by a W3C XML Schema, this refers to elements or attributes of type ID, IDREF or IDREFS. (For compatibility, the types ID, IDREF and IDREFS should only be used on attributes, but using them for elements is possible, according to XML Schema Part 2: Datatypes Second Edition.) For other schema languages, check the corresponding mechanisms for specifying IDs and references to IDs.

Expected Results

• If #1 or #2 is false, then this failure condition applies and the content fails the success criterion.

This describes a failure condition when the context needed for understanding the purpose of a link is located in content that is not programmatically determined link context. If the context for the link is not in the same sentence, paragraph, list item, or table cell as the link, then the user will not be able to find out where the link is going with any ease. If the user must leave the link to search for the context, the context is not programmatically determined link context and this failure condition occurs.

No resources available for this technique.

(none currently listed)

Procedure

1. Locate content needed to understand how link text describes the purpose of the link.

2. Check whether the content is contained in the same sentence, paragraph, list item, or table cell.

Expected Results

• If check 2 is false, the content fails the success criterion.

The objective of this technique is to describe how using text shown with a presentation that gives that text special meaning without also including the semantic markup is a failure. This includes text within the HTML or text within images.

• H42: Using h1-h6 to identify headings
• F2: Failure of SC 1.3.1 due to using CSS to create variations in presentation of text that conveys information without also using the appropriate markup or text

Procedure

1. Find any images of text on the page and any styled text which conveys information.

   1. Check that the images of text are not used to convey information which should be conveyed using markup.

   2. Check that in addition to styling, the proper semantic structure is used with the text to convey the information.

Expected Results

• Checks 1.1 and 1.2 are true.

This describes a failure condition for text alternatives on images. If there is no alt attribute, then assistive technologies are not able to identify the image or to convey its purpose to the user.

Some Assistive Technology might attempt to compensate for the missing alt text by reading the file name of the image. But it is insufficient to rely simply on the file name for many reasons. For example, file names may not be descriptive (e.g., images/nav01.gif), and technology specifications do not require descriptive file names. Some assistive technology may not read the file name if alt text is absent.

No resources available for this technique.

• H67: Using null alt text and no title attribute on img elements for images that AT should ignore

Procedure

1. identify any img, area and input elements of type "image"

2. check that the alt attribute for these elements exists.

Expected Results

• If check #2 is false, this failure condition applies and content fails the success criterion.

This describes a failure condition for all techniques involving navigation mechanisms that are repeated on multiple Web pages within a set of Web pages (Success Criterion 3.2.3). If the mechanism presents the order of links in a different order on two or more pages, then the failure is triggered.

No resources available for this technique.

(none currently listed)

Procedure

1. Check to see if a navigation mechanism is being used on more than one Web page.

2. Check the default presentation of the navigation mechanism on each page to see if the list of links are in the same relative order on each Web page.

Expected Results

• If #1 is true and #2 is false, then this failure condition applies and content fails the success criterion.

The objective of this technique is to describe the failure that occurs when the long description for non-text content does not serve the same purpose or does not present the same information as the non-text content. This can cause problems for people who cannot interpret the non-text content because they rely on the long description to provide the necessary information conveyed by the non-text content. Without a long description that provides complete information, a person may not be able to comprehend or interact with the Web page.

No resources available for this technique.

• G73: Providing a long description in another location with a link to it that is immediately adjacent to the non-text content
• G74: Providing a long description in text near the non-text content, with a reference to the location of the long description in the short description
• F13: Failure of SC 1.4.1 due to having a text alternative that does not include information that is conveyed by color differences in the image

Procedure

For all non-text content that requires a long description

1. Check that the long description serves the same purpose or presents the same information as the non-text content.

Expected Results

• If step #1 is false, then this failure condition applies and the content fails this success criterion.

This failure describes a problem that occurs when no label element is used to explicitly associate a form control with a label where the visual design uses a label.

• H44: Using label elements to associate text labels with form controls
• H65: Using the title attribute to identify form controls when the label element cannot be used

Procedure

For all input elements of type radio, checkbox, text, file or password, for all textareas, and for all select elements in the Web page:

1. Check that the visual design uses a text label that identifies the purpose of the control

2. Check that a label element associates the text with the input element

Expected Results

• If check #1 is true and check #2 is false, then this failure condition applies and the content fails these success criteria.

The objective of this failure condition is to describe a problem that occurs when changing the size of text causes text to be clipped, truncated, or obscured, so that it is no longer available to the user. In general, this failure occurs when there is no way for a user agent's layout engine to honor all the layout hints in the HTML at the new font size. Some of the ways in which this can occur include:

• Setting the overflow property of the enclosing element to hidden

• Using absolutely positioned content

• Creating popups that aren't big enough for their content at the new font size

(none currently listed)

Procedure

1. Increase the text size of the content by 200%.

2. Check that no text is clipped, truncated, or obscured.

Expected Results

• If check #2 is false, then the failure condition applies and the content fails these success criteria.

The objective of this failure is to identify examples of markup errors in element tags that could cause assistive technology to be unable to generate a satisfactory model of the page. Different user agents may implement different heuristics to recover from errors, resulting in inconsistent presentations of the page between user agents.

Some common types of problems with start and end tags that lead to this failure condition (though this is not an exhaustive list):

• Opening and closing tags that are missing the opening < and closing > brackets.

• Closing tag missing the initial / to indicate it is a closing tag.

• Attribute values that have an opening quote but not a closing quote. Attribute values must be either fully quoted or, in some markup languages, may be unquoted.

• Lack of whitespace between attributes.

• Unquoted attribute values that have whitespace in the value.

• Failure to provide a closing element tag for elements that do not accept empty-element syntax.

(none currently listed)

Procedure

1. Check the source code of pages implemented in markup languages.

2. Check whether any opening tags, closing tags or attributes are malformed.

Expected Results

• If check #2 is true, then the failure condition applies and the content does not meet this success criterion.

The objective of this failure condition is to avoid substituting characters whose glyphs look similar to the intended character, for that intended character. The Unicode character set defines thousands of characters, covering dozens of writing systems. While the glyphs for some of these characters may look like the glyphs for other characters in visual presentation, they are not processed the same by text-to-speech tools.

For example, the characters U+0063 and U+03F2 both look like the letter "c", yet the first is from the Western alphabet and the second from the Greek alphabet and not used in Western languages. The characters U+0033 and U+04E0 both look like the number "3", yet the second is actually a letter from the Cyrillic alphabet.

(none currently listed)

Procedure

1. Check the characters or character entities used to represent text.

2. If the characters used do not match the appropriate characters for the displayed glyphs in the human language of the content, then look-alike glyphs are being used.

Expected Results

• If look-alike glyphs are used, and there is not a text alternative for any range of text that uses look-alike glyphs, then the content does not meet the success criterion.

The objective of this failure condition is to avoid the use of ASCII art when a text alternative is not provided. Although ASCII art is implemented as a character string, its meaning comes from the pattern of glyphs formed by a visual presentation of that string, not from the text itself. Therefore ASCII art is non-text content and requires a text alternative. Text alternatives, or links to them, should be placed near the ASCII art in order to be associated with it.

(none currently listed)

Procedure

1. Access a page with ASCII art.

2. For each instance of ASCII art, check that it has a text alternative.

Expected Results

• If check #2 is false, then this failure condition applies and the content fails this success criterion.

This failure helps ensure that people who cannot perceive color can identify links. Link underlines or some other non-color visual distinction are required. While some links may be visually evident from page design and context, such as navigational links, links within text are often visually understood only from their own display attributes. Removing the underline and leaving only the color for such links would be a failure because there would be no other visual indication (besides color) that it is a link.

(none currently listed)

Procedure

1. Check that each link within text that is part of a sentence or paragraph (or other area where they could be mistaken as non-linked text) in the page is underlined or otherwise visually identifiable (i.e. bolded, italicized) as a link without relying on on color.

Expected Results

• If check #1 is false, then this failure condition applies and the content fails this success criterion.

The objective of this failure is to avoid situations in which multimedia alternatives are not labeled with the text for which they are alternatives. Multimedia alternatives provide enhanced access to users for whom multimedia is a more effective format than text. Since they are alternatives to text, they do not need themselves to have redundant text alternatives. However, they need to be clearly labeled with the text for which they substitute, so users can find them and so users who normally expect text alternatives to multimedia know not to look for them.

(none currently listed)

Procedure

1. Check pages that provide multimedia alternatives to text.

2. Check that multimedia is clearly labeled with the text for which it is an alternative.

Expected Results

• If check #2 is false, then this failure condition applies and the content fails these success criteria.

The objective of this failure is to avoid situations in which multimedia alternatives provide more information than the text for which they are alternatives, but do not provide their own text alternatives to provide access to the extra information. Multimedia alternatives provide enhanced access to users for whom multimedia is a more effective format than text. Since they are alternatives to text, they are do not need themselves to have redundant text alternatives in the form of captions, audio descriptions or full text alternatives. However, if they provide more information than the text for which they are an alternative, then they are more than simply alternatives but are multimedia content in their own right. In this case they are subject to the full requirements of Success Criterion 1.2.1 to provide captions and to Success Criterion 1.2.2 and 1.2.3.

(none currently listed)

Procedure

1. Check for captions on multimedia alternatives.

2. Check that the multimedia alternative does not provide more information than is presented on the page in text.

   Note: Multimedia alternatives often use different words to present what is on the page but it should not present new information on the topic of the page.

Expected Results

• If check #2 is false, then this failure condition applies and the content fails these success criteria.

The objective of this technique is to allow user to extend the default time limit by providing a mechanism to extend the time when scripts provide functionality that has default time limits. In order to allow the user to request a longer than default time limit, the script can provide a form (for example) allowing the user to enter a larger default time limit. Making this available as a preference setting allows users to indicate their requirements in advance. If warning the user a time limit is about to expire (see SCR16: Providing a script that warns the user a time limit is about to expire (SCRIPT) ), this form can be made available from the warning dialog.

Resources are for information purposes only, no endorsement implied.

1. setting session and default time limits using Java servlets

2. Overriding timeouts in peers applications

3. PHPBuilder Time-out Info

• SCR16: Providing a script that warns the user a time limit is about to expire

Procedure

1. On a Web page that uses scripts to enforce a time limit, wait until the time limit has expired.

2. Determine if an option was provided to extend the time limit.

Expected Results

• #2 is true and more time is provided to complete the interaction.

The objective of this technique is to display a dialog containing a message (alert) to the user. When the alert is displayed, it receives focus and the user must activate the OK button on the dialog to dismiss it. Since these alerts cause focus to change they may distract the user, especially when used for non-emergency information. Alerts for non-emergency purposes such as displaying a quote of the day, helpful usage tip, or count down to a particular event, are not presented unless the user enables them through an option provided in the Web page.

This technique assigns a global JavaScript variable to store the user preference for displaying alerts. The default value is false. A wrapper function is created to check the value of this variable before displaying an alert. All calls to display an alert are made to this wrapper function rather than calling the alert() function directly. Early in the page, a button is provided for the user to enable the display of alerts on the page. This technique works on a visit by visit basis. Each time the page is loaded, alerts will be disabled and the user must manually enable them. Alternatively, the author could use cookies to store user preferences across sessions.

Procedure

For a Web page that supports non-emergency interruptions using a JavaScript alert:

1. Load the Web page and verify that no non-emergency alerts are displayed.

2. Verify there is a mechanism to activate the non-emergency alerts.

3. Activate the non-emergency alerts and verify that the alerts are displayed.

Expected Results

• For a Web page that supports non-emergency interruptions using a JavaScript alert, checks 1, 2, and 3 above are true.

The objective of this technique is to notify users that they are almost out of time to complete an interaction. When scripts provide functionality that has time limits, the script can include functionality to warn the user of imminent time limits and provide a mechanism to request more time. 20 seconds or more before the time limit occurs, the script provides a confirm dialog that states that a time limit is imminent and asks if the user needs more time. If the user answers "yes" then the time limit is reset. If the user answers "no" or does not respond, the time limit is allowed to expire.

This technique involves time limits set with the window.setTimeout() method. If, for example, the time limit is set to expire in 60 seconds, you can set the time limit for 40 seconds and provide the confirm dialog. When the confirm dialog appears, a new time limit is set for the remaining 20 seconds. Upon expiry of the "grace period time limit" the action that would have been taken at the expiry of the 60 second time limit in the original design is taken.

• SCR1: Allowing the user to extend the default time limit

Procedure

On a Web page that has a time limit controlled by a script:

1. load the page and start a timer that is 20 seconds less than the time limit.

2. when the timer expires, check that a confirmation dialog is displayed warning of the impending time limit.

Expected Results

• #2 is true.

The objective of this technique is to validate user input as values are entered for each field, by means of client-side scripting. If errors are found, an alert dialog describes the nature of the error in text. Once the user dismisses the alert dialog, it is helpful if the script positions the keyboard focus on the field where the error occurred.

• G89: Providing expected data format and example

Procedure

For form fields that require specific input:

1. enter invalid data

2. determine if an alert describing the error is provided.

Expected Results

• #2 is true

The objective of this technique is to demonstrate how to correctly use an onchange event with a select element to update other elements on the Web page. This technique will not cause a change of context. When there are one or more select elements on the Web page, an onchange event on one, can update the options in another select element on the Web page. All of the data required by the select elements is included within the Web page.

It is important to note that the select item which is modified is after the trigger select element in the reading order of the Web page. This ensures that assistive technologies will pick up the change and users will encounter the new data when the modified element receives focus. This technique relies on JavaScript support in the user agent.

Resources are for information purposes only, no endorsement implied.

(none currently listed)

Procedure

1. Navigate to the trigger select element (in this example, the one to select continents) and change the value of the select.

2. Navigate to the select element that is updated by the trigger (in this example, the one to select countries).

3. Check that the matching option values are displayed in the other select element.

4. Navigate to the trigger select element, navigate through the options but do not change the value.

5. Check that the matching option values are still displayed in the associated element.

It is recommended that the select elements are tested with an assistive technology to verify that the changes to the associated element are recognized.

Expected Results

• Step #3 and #5 are true.

The objective of this technique is to illustrate the use of both keyboard-specific and mouse-specific events with code that has a scripting function associated with an event. Using both keyboard-specific and mouse-specific events together ensures that content can be operated by a wide range of devices. For example, a script may perform the same action when a keypress is detected that is performed when a mouse button is clicked. This technique goes beyond the SC requirement for keyboard access by including not only keyboard access but access using other devices as well.

In JavaScript, commonly used event handlers include, onblur, onchange, onclick, ondblclick, onfocus, onkeydown, onkeypress, onkeyup, onload, onmousedown, onmousemove, onmouseout, onmouseover, onmouseup, onreset, onselect, onsubmit, onunload. Some mouse-specific functions have a logical corresponding keyboard-specific function (such as 'onmouseover' and 'onfocus'). The keyboard event handler should be provided, that executes the same function as the mouse event handler.

The following table suggests keyboard event handlers to pair mouse event handlers.

¹ Although click is in principle a mouse event handler, most HTML user agents process this event when the control is activated, regardless of whether it was activated with the mouse or the keyboard. In practice, therefore, it is not necessary to duplicate this event. It is included here for completeness since non-HTML user agents do have this issue.

² Since the keypress event handler reacts to any key, the event handler function should check first to ensure the Enter key was pressed before proceeding to handle the event. Otherwise, the event handler will run each time the user presses any key, even the tab key to leave the control, and this is usually not desirable.

Some mouse-specific functions (such as dblclick and mousemove) do not have a corresponding keyboard-specific function. This means that some functions may need to be implemented differently for each device (for example, including a series of buttons to execute, via keyboard, the equivalent mouse-specific functions implemented).

Resources are for information purposes only, no endorsement implied.

• Overview of Creating Accessible JavaScript

• G90: Providing keyboard-triggered event handlers

Procedure

1. Find all interactive functionality

2. Check that all interactive functionality can be accessed using the keyboard alone

Expected Results

• #2 is true

The objective of this technique is to demonstrate how to use functions of the Document Object Model (DOM) to add content to a page instead of using document.write or object.innerHTML. The document.write() method does not work with XHTML when served with the correct MIME type (application/xhtml+xml), and the innerHTML property is not part of the DOM specification and thus should be avoided. If the DOM functions are used to add the content, user agents can access the DOM to retrieve the content. The createElement() function can be used to create elements within the DOM. The createTextNode() is used to create text associated with elements. The appendChild(), removeChild(), insertBefore() and replaceChild() functions are used to add and remove elements and nodes. Other DOM functions are used to assign attributes to the created elements.

Resources are for information purposes only, no endorsement implied.

• HTML 4.01 The Document Object Model, More methods from Webreference.com

(none currently listed)

Procedure

For pages that dynamically create new content:

1. Examine the source code and check that the new content is not created using document.write(), innerHTML, outerHTML, innerText or outerText.

Expected Results

• Check #1 is true.

The objective of this technique is to control blinking with script so it can be set to stop in less than three seconds by the script. Script is used to start the blinking effect of content, control the toggle between visible and hidden states, and also stop the effect at three seconds or less. The setTimeout() function can be used to toggle blinking content between visible and hidden states, and stop when the number of iterations by the time between them adds up to nearly three seconds.

Procedure

For each instance of blinking content:

1. Start a timer for 3 seconds at the start of the blink effect.

2. When the timer expires, determine if the blinking has stopped.

Expected Results

• For each instance of blinking content, #2 is true.

The objective of this technique is to avoid confusion that may be caused by the appearance of new windows that were not requested by the user. Suddenly opening new windows can disorient or be missed completely by some users. If the document type does not allow the target attribute (it does not exist in HTML 4.01 Strict or XHTML 1.0 Strict) or if the developer prefers not to use it, new windows can be opened with ECMAScript. The example below demonstrates how to open new windows with script: it adds an event handler to a link (a element) and warns the user that the content will open in a new window.

Resources are for information purposes only, no endorsement implied.

• H75: Ensuring that all id attribute values are unique for the document AND that the Web page is well-formed

Procedure

1. Activate each link in the document to check if it opens a new window.

2. For each link that opens a new window, check that it uses script.

Expected Results

• #2 is true.

The purpose of this technique is to demonstrate how to use Dynamic Web Content Accessibility to programmatically identify form components for which user input or selection are required. Dynamic Web Content Accessibility techniques provide the ability to add additional information about elements which can be programmatically determined. The user agent can provide this additional information to assistive technology for presentation to the user.

Resources are for information purposes only, no endorsement implied.

• Dynamic Web Content Accessibility Roadmap

• Role Taxonomy for Accessible Adaptable Applications

• States and Properties Module

(none currently listed)

Procedure

1. Load the page using an user agent and/or assistive technology that supports Dynamic Web Content Accessibility.

2. Navigate to each required form element and verify that "required" is spoken.

Expected Results

• Check #2 is true

The objective of this technique is to demonstrate how visual appearance may be enhanced via style sheets while still maintaining a meaningful presentation when style sheets are not applied. Using the positioning properties of CSS2, content may be displayed at any position on the user's viewport. Using structural elements ensures that the meaning of the content can still be determined when styling is not available.

Resources are for information purposes only, no endorsement implied.

• CSS-Discuss Home Page

• CSS-Discuss on CSS Layouts

• F1: Failure of SC 1.3.2 due to changing the meaning of content by positioning information with CSS

Procedure

For content which uses CSS for positioning

1. Remove the style information from the document or turn off use of style sheets in the user agent.

2. Check that the structural relations and the meaning of the content are preserved.

Expected Results

• Check #2 is true.

The objective of this technique is to supplement the link text by adding additional text that describes the unique function of the link but styling the additional text so that it is not rendered on the screen by user agents that support CSS. When information in the surrounding context is needed to interpret the displayed link text, this technique provides a complete description of the link unique function while permitting the less complete text to be displayed.

This technique works by creating a CSS selector to target text that is to be hidden. The rule set for the selector places the text to be hidden in a 1-pixel box with overflow hidden, and positions the text outside of the viewport. This ensures the text does not display on screen but remains accessible to assistive technologies such as screen readers and braille displays. Note that the technique does not use visibility:hidden or display:none properties, since these can have the unintentional effect of hiding the text from assistive technology in addition to preventing on-screen display.

No resources available for this technique.

• G91: Providing link text that describes the purpose of a link
• H30: Providing link text that describes the purpose of a link for anchor elements
• H33: Supplementing link text with the title attribute

Procedure

For each anchor element using this technique:

1. Check that an element has been defined that confines its display to a pixel and positions text outside the display with overflow hidden

2. Check that the element of that class is included in the content of the anchor

3. Check that the combined content of the anchor describes the purpose of the link

Expected Results

• All checks above are true.

The objective of this technique is to demonstrate how the visual appearance of spacing in text may be enhanced via style sheets while still maintaining meaningful text sequencing. The CSS letter-spacing property helps developers control the amount of white space between characters. This is recommended over adding blank characters to control the spacing, since the blank characters can change the meaning and pronunciation of the word.

Resources are for information purposes only, no endorsement implied.

• CSS 2.0: Letter and word spacing

• F1: Failure of SC 1.3.2 due to changing the meaning of content by positioning information with CSS
• F32: Failure of SC 1.3.2 due to using white space characters to control spacing within a word

Procedure

For each word that appears to have non-standard spacing between characters:

1. Check whether the CSS letter-spacing property was used to control spacing.

Expected Results

• Check #1 is true.

The objective of this technique is to provide a mechanism to add purely decorative images and images used for visual formatting to Web content without requiring additional markup within the content. This makes it possible for assistive technologies to ignore the non-text content. Some user agents can ignore or turn off CSS at the user's request, so that background images included with CSS simply "disappear" and do not interfere with display settings such as enlarged fonts or high contrast settings.

Background images can be included with the following CSS properties:

• background,

• background-image,

• content, combined with the :before and :after pseudo-elements,

• list-style-image.

Note: This technique is not appropriate for any image that conveys information or provides functionality, or for any image primarily intended to create a specific sensory experience.

Resources are for information purposes only, no endorsement implied.

• The background property in the CSS 2.0 specification

• The HTML 4.01 specification states that the background attribute of the body element is deprecated

• F3: Failure of SC 1.1.1 due to using CSS to include images that convey important information

Procedure

1. Check for the presence of decorative images

2. Check that they are included with CSS

Expected Results

• If #1 is true, then #2 is true.

The objective of this technique is to specify text font size proportionally so that user agents can scale content effectively. If a font-size is specified for the body element, all other elements inherit that value, unless overridden by a more specific selector.

Resources are for information purposes only, no endorsement implied.

• Cascading Style Sheets, Level 2 (CSS2), Fonts

• CSS 2 Font Size Property

• CSS-Discuss Font Size Using Percentages

• C13: Using named font sizes
• C14: Using em units for font sizes

Procedure

1. Examine all CSS properties that define font size for each rule set.

2. Check that the value is a percentage.

Expected Results

• Check #2 is true

The objective of this technique is to specify a named font size that expresses the relative font size desired. These values provide hints so that the user agent can choose a font-size relative to the inherited font-size.

Resources are for information purposes only, no endorsement implied.

• Cascading Style Sheets, Level 2 (CSS2), Fonts

• CSS 2 Font Size Property

• CSS-Discuss Font Size Using Keywords

• C12: Using percent for font sizes
• C14: Using em units for font sizes

Procedure

1. Examine all CSS properties that define font size of the CSS rule set.

2. Check that the value is one of xx-small, xx-small, x-small, small, medium, large, x-large, xx-large, xsmaller, or larger.

Expected Results

• Check #2 is true

The objective of this technique is to specify text font size in em units so that user agents can scale content effectively. Since the em is a property of the font, it scales as the font changes size. If a font-size is specified for the body element, all other elements inherit that value, unless overridden by a more specific selector.

Resources are for information purposes only, no endorsement implied.

• Cascading Style Sheets, Level 2 (CSS2), Fonts

• CSS 2 Font Size Property

• CSS-Discuss Font Size Using Ems

• C12: Using percent for font sizes
• C13: Using named font sizes

Procedure

1. Examine all CSS properties that define font size for each rule set.

2. Check that the value is expressed in em units.

Expected Results

• Check #2 is true

The objective of this technique is to provide a mechanism to bypass blocks of material that are repeated on multiple Web pages by skipping directly to the main content of the Web page. The first interactive item in the Web page is a link to the beginning of the main content. Activating the link sets focus beyond the other content to the main content. This technique is most useful when a Web page has one main content area, rather than a set of content areas that are equally important. [LC-701]

Resources are for information purposes only, no endorsement implied.

• Skip Navigation Links

(none currently listed)

Procedure

1. Check that a link is the first focusable control on the Web page.

2. Check that the description of the link communicates that it links to the main content.

3. Check that activating the link moves the focus to the main content.

4. Check that after activating the link, the keyboard focus has moved to the main content

Expected Results

• All checks above are true.

The objective of this technique is to provide a way to pause movement or scrolling of content. If the user needs to pause the movement, to reduce distraction or to have time to read it, they can do so, and then restart it as needed. This mechanism can be provided either through interactive controls that conform to WCAG or through keyboard shortcuts. If keyboard shortcuts are used, they are documented.

Procedure

On a page with moving or scrolling content,

1. Use the mechanism provided in the Web page or by the user agent to pause the moving or scrolling content.

2. Check that the moving or scrolling has stopped and does not restart by itself.

3. Use the mechanism provided to restart the moving content.

4. Check that the movement or scrolling has resumed from the point where it was stopped.

Expected Results

• #2 and #4 are true.

The objective of this technique is to provide users with all the time they need to complete an activity. This technique involves providing a specified activity which does not require timed interaction. Users are allowed as much time as they need to interact with the activity.

Resources are for information purposes only, no endorsement implied.

• Resource-Oriented vs. Activity-Oriented Web Services

• Top Ten Web Design Mistakes of 2005

Procedure

1. Determine if any timed interactions are present.

Expected Results

• #1 is false.

The objective of this technique is to all additional audio description to be inserted into a multimedia presentation when there is not enough time in the gaps int the dialog. This is done by simply freezing the image so that additional audio description of the video can be played. When the description is finished, the multimedia continues.

This technique provides people who are blind or who otherwise would miss information presented visually with additional audio description beyond that which can be provided by standard audio description. Often the gaps in dialog are insufficient to allow enough audio description to be inserted to cover all the important visual information being presented. This technique freezes the multimedia presentation to allow additional audio description to be played. The multimedia presentation is then resumed.

Because it disrupts viewing for those who do not need the additional description, techniques that allow you to turn the feature on and off are often provided. Alternately, versions with and without the additional description can be provided.

Resources are for information purposes only, no endorsement implied.

• SM1: Adding extended audio description in SMIL 1.0
• SM2: Adding extended audio description in SMIL 2.0

Procedure

1. Play multimedia with extended audio description enabled

2. Check to see if multimedia freezes from time to time to allow audio description to convey important information regarding visual content

Expected Results

• #2 is true

The objective of this technique is to allow users who cannot hear to be able to access real-time multimedia broadcasts. It is more difficult to create accurate real-time captions because there is little time to correct mistakes or to listen a second time or consult someone to be sure the words are accurately reproduced. It is also harder to simplify or paraphrase information if it is flowing too quickly.

Real-time typing text entry techniques exist using stenographic and rapid typing technologies. Re-voicing speech-to-text (where a person listens to speech and then carefully re-voices it into a computer trained to their speech) is used today for telephone relay services and may be used in the future for captioning. Eventually speech-to-text with correction will be possible.

Resources are for information purposes only, no endorsement implied.

(none)

• G87: Providing closed captions
• G93: Providing open (always visible) captions

Procedure

1. a procedure and policy are in place to ensure that captions are delivered in real-time

Expected Results

• #1 is true

The objective of this technique is to allow assistive technology to understand Web content so that it can convey equivalent information to the user through an alternate user interface.

Sometimes content is not created using markup language but rather using a programming language or tools. In many cases, these technologies have interface components that are already programmed to interface with accessibility APIs. If and author uses these components and fills in the properties (e.g. name, etc) the resulting user interface components in the content will be accessible to assistive technology.

However, if an author wants to create a user interface component that is new and they cannot use standard components, then they need to be sure to add the accessibility provisions themselves - and implement them in a way that is compatible with the accessibility API.

Resources are for information purposes only, no endorsement implied.

(none currently listed)

Procedure

1. Render content using an accessible User Agent

2. Use an Accessibility Tool designed for the Accessibility API of the User agent to evaluate each user interface component

3. Check that name and role for each user interface component is found by the tool.

4. Change the values on the component

5. Check that the Accessibility tool is alerted.

Expected Results

• Step #3 and #5 are true for each user interface component

The objective of this technique is to minimize the distraction caused by blinking content and enable users to re-focus on the other content on the page.

Blinking content can be created using a variety of technologies, many of which include options to loop blinking content continuously or to otherwise specify the amount of time the blinking content is displayed. Limiting the blinking of content to three seconds minimizes the distraction that blinking can cause. This will benefit people with certain types of learning disabilities and people with low vision.

Procedure

1. Find all items that blink.

2. For each item that blinks, determine if the interval between the start and end of the blinking is less than three seconds.

Expected Results

• #2 is true.

The objective of this technique is to provide information to users about what will happen when a change to a form control results in a change of context. Because changing the value of a form control does not typically result in a change of context, it is important that authors provide instructions that make the user aware of the behavior in advance. Where possible, it is a good idea to programmatically associate the instructions describing the change with the form control itself.

Resources are for information purposes only, no endorsement implied.

(none currently listed)

Procedure

• Locate content where changing the setting of a form control results in a change of context

• Check to see that an explanation of what will happen when the control is changed is available prior to the controls activation

Expected Results

• Check #2 is true.

The objective of this technique is to ensure that when color is used to convey information, such as required form fields, the information conveyed by the color is also conveyed explicitly in text.

No resources available for this technique.

(none currently listed)

Procedure

For each item where color is used to convey information:

1. Check that the information conveyed is also available in text and that the text is not conditional content.

Expected Results

• Check #1 is true.

The purpose of this technique is to allow people who have photosensitive seizures to view Web sites without encountering material that is likely to cause a seizure. Warnings can be provided but people may miss them and children may not be able to read or understand them. With this technique all material is checked and if it violates flash or red flash thresholds it is either not put on the site or it is modified so that it does not violate the thresholds.

Resources are for information purposes only, no endorsement implied.

• Harding FPA Web Site

• Trace Center Photosensitive Epilepsy Analysis Tool (PEAT)

(none currently listed)

Procedure

1. Check to see if content violates the flash and/or red flash thresholds by either

   • visually checking that there are no more than 2 flashes of any kind in a row OR

   • using a tool that will check for General Flash or Red Flash thresholds automatically

Expected Results

• Step 1 is false

The objective of this technique is to make sure that users can read text that is presented over a background. This technique goes beyond the 5:1 contrast technique to provide a higher level of contrast to make it easier for people with low vision to read.

If the background is a solid color (or all black or all white) then the contrast ratio of the text can be maintained by making sure that each of the text letters have a 7:1 contrast ratio with the background.

If the background or the letters vary in relative luminance (or are patterned), then the background around the letters can be chosen or shaded so that the letters maintain a 7:1contrast ratio with the background behind them even if they do not have that contrast ratio with the entire background.

The contrast ratio can sometimes be maintained by changing the relative luminance of the letters as the relative luminance of the background changes across the page.

Another method is to provide a halo around the text that provides the necessary contrast ratio if the background image or color would not normally be sufficiently different in relative luminance.

Resources are for information purposes only, no endorsement implied.

• Contrast Analyser – Application

• Contrast Ratio Analyser - online service

• Colour Contrast Analyser - Firefox Extension

• Color Contrast Samples

• Atypical colour response

(none currently listed)

Procedure

1. Measure the relative luminance of each letter (unless they are all uniform) using the formula:

   • L = 0.2126 * R + 0.7152 * G + 0.0722 * B where R, G and B are defined as:

     • if R_sRGB <= 0.03928 then R = R_sRGB/12.92 else R = ((R_sRGB+0.055)/1.055) ^ 2.4

     • if G_sRGB <= 0.03928 then G = G_sRGB/12.92 else G = ((G_sRGB+0.055)/1.055) ^ 2.4

     • if B_sRGB <= 0.03928 then B = B_sRGB/12.92 else B = ((B_sRGB+0.055)/1.055) ^ 2.4

     and R_sRGB, G_sRGB, and B_sRGB are defined as:

     • R_sRGB = R_8bit/255

     • G_sRGB = G_8bit/255

     • B_sRGB = B_8bit/255

     The "^" character is the exponentiation operator.

   Note: For aliased letters, use the relative luminance value found two pixels in from the edge of the letter.

2. Measure the relative luminance of the background pixels immediately next to the letter using same formula.

3. Calculate the contrast ratio using the following formula.

   • (L1 + 0.05) / (L2 + 0.05), where

     • L1 is the relative luminance of the lighter of the foreground or background colors, and

     • L2 is the relative luminance of the darker of the foreground or background colors.

4. Check that the contrast ratio is equal to or greater than 7:1

Expected Results

• #4 is true

The objective of this technique is to make sure that users can read text that is presented over a background. For Success Criterion 1.4.3, this technique describes the minimum contrast ratio for text that is less than 18 point (if not bold) and less than 14 point (if bold). For Success Criterion 1.4.5, this technique relaxes the 7:1 contrast ratio requirement for text that is at least 18 point (if not bold) or at least 14 point (if bold).

If the background is a solid color (or all black or all white) then the relative luminance of the text can be maintained by making sure that each of the text letters have 5:1 contrast ratio with the background.

If the background or the letters vary in relative luminance (or are patterned) then the background around the letters can be chosen or shaded so that the letters maintain 5:1 contrast ratio with the background behind them even if they do not have that contrast ratio with the entire background.

The contrast ratio can sometimes be maintained by changing the relative luminance of the letters as the relative luminance of the background changes across the page.

Another method is to provide a halo around the text that provides the necessary contrast ratio if the background image or color would not normally be sufficiently different in relative luminance.

Resources are for information purposes only, no endorsement implied.

• Contrast Analyser – Application

• Contrast Ratio Analyser - online service

• Colour Contrast Analyser - Firefox Extension

• Color Contrast Samples

• Atypical colour response

(none currently listed)

Procedure

1. Measure the relative luminance of each letter (unless they are all uniform) using the formula:

   • L = 0.2126 * R + 0.7152 * G + 0.0722 * B where R, G and B are defined as:

     • if R_sRGB <= 0.03928 then R = R_sRGB/12.92 else R = ((R_sRGB+0.055)/1.055) ^ 2.4

     • if G_sRGB <= 0.03928 then G = G_sRGB/12.92 else G = ((G_sRGB+0.055)/1.055) ^ 2.4

     • if B_sRGB <= 0.03928 then B = B_sRGB/12.92 else B = ((B_sRGB+0.055)/1.055) ^ 2.4

     and R_sRGB, G_sRGB, and B_sRGB are defined as:

     • R_sRGB = R_8bit/255

     • G_sRGB = G_8bit/255

     • B_sRGB = B_8bit/255

     The "^" character is the exponentiation operator.

   Note: For aliased letters, use the relative luminance value found two pixels in from the edge of the letter.

2. Measure the relative luminance of the background pixels immediately next to the letter using same formula.

3. Calculate the contrast ratio using the following formula.

   • (L1 + 0.05) / (L2 + 0.05), where

     • L1 is the relative luminance of the lighter of the foreground or background colors, and

     • L2 is the relative luminance of the darker of the foreground or background colors.

4. Check that the contrast ratio is equal to or greater than 5:1

Expected Results

The contrast ratio is equal to or greater than 5:1

• #4 is true.

The objective of this technique is to avoid flashing at rates that are known to cause seizures if the flashes are bright and large enough. Since some users may be using screen enlargers, this technique limits the flashing of any size content to no more than three flashes in any 1-second period.

Examples of 3.5 flashes or seven transitions:

• STARTING DARK-LIGHT-DARK-LIGHT-DARK-LIGHT-DARK-LIGHT or

• STARTING LIGHT-DARK-LIGHT-DARK-LIGHT-DARK-LIGHT-DARK.

Resources are for information purposes only, no endorsement implied.

• Trace Center Photosensitive Epilepsy Analysis Tool (PEAT)

• G15: Ensuring that content does not violate the general flash threshold or red flash threshold

Procedure

1. Check that there are no more than three flashes during any 1-second period.

2. If there are three flashes, check that the Light/Dark status at the end of the 1-second period is the same as at the start.

Expected Results

• Both Step 1 and Step 2 are true.

The objective of this technique is to ensure that users can always access an accessible version of the content. When content is provided in a format that does not conform to WCAG, the site as a whole can still conform if alternate versions of the inaccessible content are provided. The conformance criterion requires that alternate versions are available "from the nonconforming content or its URI." It is the intent of that wording that it can be sufficient to provide a link to conforming content from the nonconforming content (see G136: Providing a link at the beginning of the nonconforming content that points to an alternate version that does meet WCAG 2.0 at the level claimed ).

In order for the link to alternate content to fulfill its intent, the link needs to conform to WCAG requirements, that is, be accessible. In some technologies, even though the content as a whole may not conform, a link can be provided that does conform. In other technologies, however, it is not even possible to provide a link to alternate content within that technology that conforms. Users may be unable to find the alternate content if the only pointer is in an inaccessible technology.

This technique describes how to provide alternate content in such a situation. In this technique, the WCAG conforming version contains a link to the nonconforming version. This way, users access the conforming content, and only access the nonconforming content if they wish, via a link. In order to ensure users do not accidentally get "stuck" in inaccessible content, the nonconforming version is excluded from search engine results, site maps (unless the conforming version is also included), etc.

• G136: Providing a link at the beginning of the nonconforming content that points to an alternate version that does meet WCAG 2.0 at the level claimed

Procedure

Where WCAG conforming alternatives are provided for nonconforming content:

1. Check that there is a link to the nonconforming content from the conforming content.

2. Check that the nonconforming content does not appear in search engine results, site maps, and the site's regular navigation.

Expected Results

• #1 and #2 are true.

The objective of this technique is to ensure that keyboard users do not become trapped in a subset of the content that can only be exited using a mouse or pointing device. A common example is content rendered by plug-ins. Plug-ins are user agents that render content inside the user agent host window and respond to all user actions that takes place while the plug-in has the focus. If the plug-in does not provide a keyboard mechanism to return focus to the parent window, users who must use the keyboard may become trapped in the plug-in content.

This problem can be avoided by using one of the following mechanisms to provide a way for users to escape the subset of the content:

• Ensuring that the keyboard function for advancing focus within content (commonly the tab key) exits the subset of the content after it reaches the final navigation location.

• Providing a keyboard function to move the focus out of the subset of the content. Be sure to document the feature in an accessible manner within the subset.

• If the subset of the content does natively provide a "move to parent" keyboard command, documenting that command before the user enters the plug-in so they know how to get out again.

No resources available for this technique.

(none currently listed)

Procedure

1. tab through content from start to finish.

2. check to see if keyboard focus is trapped in any of the content such that the person cannot move out of any part of the content and continue through the rest of the content.

Expected Results

• #2 is false

The objective of this technique is to identify the purpose of a link from the link and its sentence context. The sentence enclosing the link provides context for an otherwise unclear link. The description lets a user distinguish this link from links in the Web page that lead to other destinations and helps the user determine whether to follow the link. Note that simply providing the URI of the destination is generally not sufficiently descriptive.

No resources available for this technique.

• G91: Providing link text that describes the purpose of a link
• H77: Identifying the purpose of a link using link text combined with its enclosing list item
• H78: Identifying the purpose of a link using link text combined with its enclosing paragraph
• H79: Identifying the purpose of a link using link text combined with its enclosing table cell and associated table headings
• C7: Using CSS to hide a portion of the link text

Procedure

For each link in the content that uses this technique:

1. Check that the link is part of a sentence

2. Check that text of the link combined with the text of its enclosing sentence describes the purpose of the link

Expected Results

• The above checks are true.

The objective of this technique is to allow users who cannot hear or read text rapidly to be able to access multimedia material.

For those who communicate primarily in sign language it is sometimes less preferable and sometimes not possible for them to read and understand text at the rate it is presented in captions. For these latter individuals it is important to provide sign language presentation of the audio information.

One universally compatible way of doing this is to simply embed a video of the sign language interpreter in the video stream. This has the disadvantage of providing a lower resolution image that cannot be easily enlarged without enlarging the entire image.

Resources are for information purposes only, no endorsement implied.

• Guidelines for the Production of Signing Books

  • "Sign Language presentation" gives a broad overview of issues to consider when filming sign language interpreters. Includes discussion of signing both written and spoken originals.

  • Techniques for filming are discussed in chapter 12, “Filming the Signer(s)”.

  • Useful information about how to display the sign language interpreter in relation to the original multimedia content is provided in Chapter 13, "Editing"

    Note: These techniques may need to be adapted for Web-based presentation.

(none currently listed)

Procedure

1. Have someone watch the program who can hear and is familiar with the sign language being used.

2. Check to see if there is a sign language interpreter on screen.

3. Check to see that dialog and important sounds are being conveyed by the interpreter visible on screen.

Expected Results

• #2 and #3 are true

The objective of this technique is to make the definition of a word, phrase, or abbreviation available by providing the definition, either within the same Web page or in a different Web page, and establishing a link between the item and its definition.

Links are a powerful option for providing access to the definition of a word, phrase, or abbreviation. A user can use the link to find the definition quickly and easily, and then return to his place in the content via the user agent's Back button.

No resources available for this technique.

(none currently listed)

Procedure

For each word, phrase, or abbreviation to be defined:

1. Check that at least the first instance of the item is a link.

2. Check that each link navigates to the definition of the item.

Expected Results

• Checks #1 and #2 are true.

The objective of this technique is to allow authors to include sound behind speech without making it too hard for people with hearing problems to understand the speech. Making sure that the foreground speech is 20 db louder than the backgound sound makes the speech 4 times louder than the background audio. For information on Decibels (dB), refer to About Decibels