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Posts Tagged ‘best practices’

Best Practices for Accessible Stylesheets

May 1st, 2009 Michael Gaigg 4 comments

Cascading Style Sheets (CSS), or short Stylesheets, is a language used to describe the presentation (that is, the look and formatting) of a document written in a markup language like HTML.

The stylesheet language as described in CSS level 2 revision 1 helps to separate presentation from structure and thus adds flexibility to the look and feel of a web page. Stylesheets are useful for the following reasons:

  • Can be re-used for many documents
  • Saves download times by caching by the browser
  • Presentational changes are fast and easy and only in one document
  • Development can be done independently from content and logic
  • Increases ability to program for device independence
  • Application of different styles for different output formats (e.g. print)

Basic Rules

  • Add Stylesheets whenever possible (minimize number of stylesheets)
  • Use them consistently across all pages
  • Use linked stylesheets rather than embedded styles; avoid inline stylesheets
  • Stylesheets do not substitute correct and meaningful structure

Best Practices

Level 1

Level 1 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Organize documents so they may be read without style sheets 6.1 d Ensure that important content appears in the document object and is not generated by style sheets (i.e. through :before and :after pseudo-elements).

Level 2


Level 2 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Use style sheets to control layout and presentation 3.3 n/a
<HEAD>
<TITLE>Drop caps</TITLE>
<EM class=”highlight” title=”provide STYLE element”>STYLE</EM> type=”text/css”>
.dropcap { font-size : 120%; font-family : Helvetica }
</EM class=”highlight” title=”provide STYLE element”>STYLE</EM>>
</HEAD>
<BODY>
<P><SPAN class=”dropcap”>O</SPAN>nce upon a time…
</BODY>

Level 3

Level 3 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Create a style of presentation that is consistent across pages 14.3 n/a A consistent style of presentation on each page allows users to locate navigation mechanisms more easily but also to skip navigation mechanisms more easily to find important content.

Template

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<link rel="stylesheet" type="text/css" href="BaseStyleSheet.css" />
</head>
<body>
Hello World
</body>
</html>


/* Base CSS Document */
/**
Elements
*/
html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, font, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td {
margin: 0;
padding: 0;
border: 0;
outline: 0;
font-weight: inherit;
font-style: inherit;
font-size: 100%;
font-family: inherit;
vertical-align: baseline;
}
/* remember to define focus styles! */
:focus {
outline: 0;
}
body {
line-height: 1;
color: black;
background: white;
font-family: Arial, Helvetica, sans-serif;
}
ol, ul {
list-style: none;
}
/* tables still need 'cellspacing="0"' in the markup */
table {
border-collapse: separate;
border-spacing: 0;
}
caption, th, td {
text-align: left;
font-weight: normal;
}
blockquote:before, blockquote:after,
q:before, q:after {
content: "";
}
blockquote, q {
quotes: "" "";
}
/**
Classes
*/
/**
IDs
*/

References

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Best Practices for Accessible Frames

February 20th, 2009 Michael Gaigg No comments

Frames are hardly used anymore (thanks God) but they can be useful and a good method to organize huge sites with lots of content, e.g. document libraries, API documentation, etc.

The 508 standard has no objection against frames and screen readers can handle frames well even though it might be difficult to comprehend the structure. The following basic rules and best practices outline how one can make frames accessible:

Basic Rules

  • Title frameset and frames with meaningful names (descriptive instead of location, i.e. ‘navigation’ instead of ‘left’)
  • Provide an alternative (NOFRAMES tag)

Best Practices

Level 1

Level 1 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Provide a text equivalent for every non-text element 1.1 a <FRAMESET cols=”50%,50%” title=”…”>

<FRAME src=”sitenavbar.htm” …>

<FRAME src=”story.htm” …>

<NOFRAMES>

[<A href="sitenavbar.htm" title="...">Table of Contents</A>] [<A href="story.htm" title="...">Story</A>]

</NOFRAMES>

</FRAMESET>
Title each frame to facilitate frame identification and navigation 12.1 i <FRAMESET cols=”10%, 90%” title=”Our library of electronic documents”>

<FRAME src=”nav.html” title=”Navigation bar”>

<FRAME src=”doc.html” title=”Documents”>

</FRAMESET>

Level 2

Level 2 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Describe the purpose of frames and how frames relate to each other if it is not obvious by frame titles alone 12.2 i <FRAME src=”sitenavbar.htm” name=”navbar” title=”Sitewide navigation bar” longdesc=”frameset-desc.htm#navbar”>

<FRAME src=”story.htm” name=”story” title=”Selected story – main content” longdesc=”frameset-desc.htm#story”>

Template

<frameset cols="50%,50%" title="Our library of electronic documents">
<frame src="navigation.htm" title="Navigation bar">
<frame src="start.htm" title="Main Content">
<noframes>
[<a href="navigation.htm" title="Navigation bar">Table of Contents</a>]
</noframes>
</frameset>

References

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Best Practices for accessible Images

January 7th, 2009 Michael Gaigg No comments

Graphics can be of great benefit to the accessibility of a Web page by providing

  • Illustrations
  • Icons
  • Animations
  • other visual cues that aid comprehension for sighted individuals

When designing for people with disabilities too often we forget that we are not designing only for the blind. We must consider disabilities of all types. Graphics can be useful especially to individuals with certain reading disabilities, learning disabilities, attention deficit disorders, or cognitive disabilities.

Basic Rules

  • Do not use color alone to convey meaning
  • Choose contrast so that text is easily distinguishable from the background
  • Communicate the purpose of the graphic (not its appearance) through meaningful alternative text
  • When graphics require complex descriptions use the longdesc attribute, a link to an alternative page, a description in the context itself, or a “D” link
  • Use empty alt text for decorative, transparent, spacer, and redundant images
  • Try to limit the amount of text in graphics
  • Do not use effects that flicker or produce a strobe-like effect
  • Use images as backgrounds only if they do not convey important content (since it is impossible to add alt text to background images)

Best Practices

Level 1

Level 1 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Ensure that all information conveyed with color is also available without color 2.1 c Ensure that information is available through other style effects (e.g., a font effect), through context (e.g,. comprehensive text links) or through mark-up (e.g., the title attribute).
Until user agents allow users to control flickering, avoid causing the screen to flicker 7.1 j n/a
Provide text equivalent for Images, graphical or animated buttons, spacers, bullets 1.1 a <FORM action=”…” method=”post”>

  <INPUT type=”button” alt=”Click this button to verify form” value=”Verify” onclick=”verify()”>

  <INPUT type=”image” name=”submit” src=”button.gif” alt=”Submit form”>

</FORM>

Level 2

Level 2 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen 2.2 c For more information check the online paper about Effective Color Contrast.
When an appropriate markup language exists, use markup rather than images to convey information 3.1 n/a Mark up complex equations with e.g. MathML.
Avoid causing content to blink 7.2 n/a n/a
Avoid movement in pages 7.3 n/a i.e., hide/show content or change presentation (movement and colors).

Level 3

Level 3 Checkpoints – Section 508 Compliancy Standards
Description W3C 508 Example
Supplement text with graphic or auditory presentations where they will facilitate comprehension of the page 14.2 n/a n/a

References

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Best Practices for accessible Tables

November 20th, 2008 Michael Gaigg 1 comment

The purpose of a table is to layout data. Unlike regular text, tables are generally difficult to comprehend. It takes time and effort to understand the structure, capture the data and interpret its meaning. This is even more difficult when the table is viewed and read out by a screenreader. Additional attributes are needed to relate headers with column and rows.

Tables might be used to layout content. The current recommendation for content tables is to explicitely state this purpose upfront so that users with screenreaders can avoid investigating the table’s structure. Convey this meaning using the summary attribute:

<table border="0" summary="Layout table with two columns: menu and content">

Basic Rules

General:

  • Use proper HTML
  • Use tables for displaying tabular data
  • Use block elements (e.g. DIV) and CSS for layout purposes
  • Use proportional sizing rather than absolute sizing

Data Tables:

  • Describe tables with a name or title (caption tag)
  • Provide a summary (summary attribute)
  • Designate Row and Column Headers (TH tag)
  • Associate the data cells with the appropriate headers (scope & id attributes)
  • Avoid spanned rows or columns (workaround: normalize table)
  • Avoid tables with more than two levels of row and/or column headers

Layout Tables:

  • Linearize content (literal order in the code equals the linearized reading order)
  • Use the simplest table configuration possible

Best Practices

Level 1

Level 1 Checkpoints - Section 508 Compliancy Standards
Description W3C 508 Example
For data tables, identify row and column headers 5.1 (g) <TR>
<TH>Name</TH>
<TH>Cups</TH>
<TH abbr="Type">Type of Coffee</TH>
<TH>Sugar?</TH>
</TR>
For data tables that have two or more logical levels of row or column headers, use markup to associate data cells and header cells 5.2 (h) <TABLE border="1">
  <CAPTION>Travel Expense Report</CAPTION>
  <TR>
    <TH></TH>
    <TH id="header2" axis="expenses">Meals
    <TH id="header3" axis="expenses">Hotels
    <TH id="header4" axis="expenses">Transport
    <TD>subtotals</TD>
  <TR>
    <TH id="header6" axis="location">San Jose
    <TH> <TH> <TH> <TD>
  <TR>
    <TD id="header7" axis="date">25-Aug-97
    <TD headers="header6 header7 header2">37.74
    <TD headers="header6 header7 header3">112.00
    <TD headers="header6 header7 header4">45.00
    <TD>
  <TR>
    <TD id="header8" axis="date">26-Aug-97
    <TD headers="header6 header8 header2">27.28
    <TD headers="header6 header8 header3">112.00
    <TD headers="header6 header8 header4">45.00
    <TD>
  <TR>
    <TD>subtotals
    <TD>65.02
    <TD>224.00
    <TD>90.00
    <TD>379.02
</TABLE>

Level 2

No Level 2 requirements.

Level 3

Level 3 Checkpoints - Section 508 Compliancy Standards
Description W3C 508 Example
Provide summaries for tables 5.5 n/a <TABLE summary="This table charts the number of cups of coffee ...">
Provide abbreviations for header labels 5.6 n/a <TABLE ...>
<TH scope="col">Name</TH>
<TH scope="col">Cups</TH>
<TH scope="col" abbr="Type">Type of Coffee</TH>
<TH scope="col">Sugar?</TH>
</TABLE>
Provide a linear text alternative (on the current page or some other) for all tables that lay out text in parallel, word-wrapped columns 10.3 n/a n/a

References

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Best Practices for accessible Links

October 28th, 2008 Michael Gaigg No comments

It is essential that users can find, identify, and comprehend hypertext links quickly. Even though there are no Level 1 (A) checkpoints associated with links it is pretty easy to fulfill Level 2 and even Level 3. It’s definitely worthwhile the little effort with the added benefit that e.g. most browsers render the title attribute as a tooltip.

Basic Rules

See also my Design Guidelines for Links.

  • Contrast link text color and regular text color
  • Underline link text
  • Ensure link text is descriptive of its destination
  • Make visited links change color
  • Limit link text to a maximum of four words
  • Place important words at the front of link text
  • Minimize amount of links to seven (excluding the menu) unless they are presented in a clear structure
  • Use meaningful pathnames when creating directory structure

Best Practices

Level 1

No Level 1 requirements.

Level 2

Level 2 Checkpoints – Section 508 Compliancy Standards
Checkpoint Description W3C 508 Example
Links Clearly identify the target of each link 13.1 n/a <A href=”my-doc.html”>My document is available in HTML</A>,<A href=”my-doc.pdf” title=”My document in PDF”>PDF</A>,

<A href=”my-doc.txt” title=”My document in text”>plain text</A>

Level 3

Level 3 Checkpoints – Section 508 Compliancy Standards
Checkpoint Description W3C 508 Example
Links Create a logical tab order 9.4 n/a <A tabindex=”2″ href=”link2.txt”">Link 2</A><A tabindex=”1″ href=”link1.txt”>Link 1</A>

<A tabindex=”3″ href=”link3.txt”>Link 3</A>
Links Provide keyboard shortcuts to important links 9.5 n/a <A accesskey=”2″ href=”link2.txt”">Link 2</A><A accesskey=”1″ href=”link1.txt”>Link 1</A>

<A accesskey=”3″ href=”link3.txt”>Link 3</A>
Links Include non-link, printable characters (surrounded by spaces) between adjacent links 10.5 n/a [<A href="a.htm">Link A</A>] [<A href="b.html">Link B</A>] or<A href=”a.htm”>Link A</A> | <A href=”b.html”>Link B</A>

Templates

Find out more about <a title="Michael Gaigg IT Solutions Webpage" href="http://www.mgitsolutions.com/">IT Solutions</a>

References

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Best Practices for accessible Content

October 21st, 2008 Michael Gaigg No comments

People rarely read Web pages, they scan the page! As a result, Web pages have to follow Design Guidelines for Content that enable them to quickly identify headings, titles, links and other important elements to orient themselves. What else has to be done to be Section 508 compliant?

Basic Rules

  • Don’t rely on color alone
  • Identify the language used throughout the document and identify changes
  • Use correct markup to emphasize important content
  • Be clear and precise in the choice of wording and language

Best Practices

Level 1

Level 1 Checkpoints – Section 508 Compliancy Standards
Checkpoint Description W3C 508 Example
Color Ensure that all information conveyed with color is also available without color 2.1 (c) Ensure that information is available through other style effects (e.g., a font effect), through context (e.g,. comprehensive text links) or through mark-up (e.g., the title attribute).
Language Clearly identify changes in the natural language of a document’s text and any text equivalents 4.1 n/a And with a certain <SPAN lang=”fr”>je ne sais quoi</SPAN>,
she entered both the room, and his life, forever. <Q>My name
is Natasha,</Q> she said. <Q lang=”it”>Piacere,</Q>
he replied in impeccable Italian, locking the door.
Language Use the clearest and simplest language appropriate for a site’s content 14.1 n/a n/a

Level 2

Level 2 Checkpoints – Section 508 Compliancy Standards
Checkpoint Description W3C 508 Example
Blinking Avoid causing content to blink 7.2 n/a n/a
Movement Avoid movement in pages 7.3 n/a i.e., hide/show content or change presentation (movement and colors).

Level 3

Level 3 Checkpoints – Section 508 Compliancy Standards
Checkpoint Description W3C 508 Example
Text Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen 2.2 (c) For more information check the online paper about “Effective Color Contrast” at lighthouse.org (http://www.lighthouse.org/accessibility/effective-color-contrast/).
Abbreviations Specify the expansion of each abbreviation in a document where it first occurs 4.2 n/a <ABBR title=”social security number”>SS#</ABBR>

or ASCII art:<ABBR title=”smiley in ASCII art”>:-)</ABBR>
Acronyms Specify the expansion of each acronym in a document where it first occurs 4.2 n/a Welcome to the <ACRONYM title=”World Wide Web”>WWW</ACRONYM>
Language Identify the primary natural language of a document 4.3 n/a <HTML lang=”en”>

Templates

<HTML xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

<ABBR title="social security number">SS#</ABBR>

<ACRONYM title="Geographical Information System">GIS</ACRONYM>

References

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