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Accessibility In ASP.NET Web Site

Accessibility by term means something which is accessible. An accessible website is one which is accessible by everyone. People with any kind of disabilities also should be able to use a website same like a normal person. Major efforts have been done in standardizing the approach by World Wide Web Consortium's and Web Accessibility Initiative. Their efforts have also produced a set of guidelines which comes under DDA (Disability Discrimination Act). There are set of standards as WCAG 1.1, WCAG 1.2, WCAG 1.3 and Access Board Section 508. These standards have a set of checklist which one has to consider making a website accessible.


Web Accessibility Initiative (WAI) has taken steps to prepare guidelines to make websites, software, and tools to be accessible. Websites are vital part of society as the trend of social websites are increasing day by day. So people with disabilities also need to be a valid user of the website. Otherwise, say you have a "Social website", they would be only accessible to say 65% normal customers, and 35% of disabled persons would not be able to see or check out what your business is. This way not only you are blocking your clientage but also being unfair to them by not allowing them to access your product.

How can we say that a person is disabled, and how can we tackle this in our website.

1- A person comes to your website for shopping but he is color blind


We can use proper style sheets to manage colors and text sizes so any user can adjust according to need.

We normally see such panels on top of accessible websites to adjust the visual parameters

2- Say you are running a music website, and a deaf persons visits your website, how will you tackle this as the visitor would not be able to listen as he is disabled.


You need to add audio captions in place of the music control, so that the content is accessible to them as well.

3- People visit your website with Dyslexia problem, in this case user find it difficult to interpret the written content on the website, it is a neurological disability, and is not an intellectual disability.


More options to search pages, provide a graphical representation as well.

4- Suppose a visitor is deaf and blind both


Use Style sheets, accessible multimedia with audio captions if any, should be independent of devices, use proper Xhtml techniques

There can be many more scenarios that exists and can be tackled if we see the complete checklist of World Wide Web Consortium's and Web Accessibility Initiative.

Microsoft based websites developed in ASP.NET can be optimized and configured of Web accessibility standards by considering the rules in our mind. Let's take an example site and try to see how we can develop an accessible website and what steps we need to make to make this website accessible.

Let's create an Ajax Enabled ASP.NET website

Clicking on "OK" button will generate the website with a default page, and put a code in it as well. Let's analyze the code below which .net produces for us and see if it is accessible.


    1 <%@ Page Language="VB" AutoEventWireup="true" CodeFile="Default.aspx.vb" Inherits="_Default" %>
    3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    4 <html xmlns="http://www.w3.org/1999/xhtml">
    5 <head runat="server">
    6     <title>Untitled Page</title>
    7 </head>
    8 <body>
    9     <form id="form1" runat="server">
   10         <asp:ScriptManager ID="ScriptManager1" runat="server" />
   11         <div>
   12         </div>
   13     </form>
   14 </body>
   15 </html>


Visual Studio.net has a built in accessibility checklist option in the toolbar.

Click icon

A window will popup like below:


Here we can see that WCAG Priority checklist 1 is disabled as that has the most common points we need to adhere in our coding and are sort of compulsory as well. Lets click validate to see that we have any "Errors", "Warnings" or "Manual CheckList" in our code which we have missed. Note here that we need to fully remove the Warnings as they are most important, and then on second priority we need to check for errors and on least priority are our Manual Checklists.


Click on image to see larger


Here we can see that though we have not done any coding yet, but Microsoft has checked the code against the standardized checklist, and produced for us a little error report, luckily we do not have any errors yet. We receive set of warnings and messages, which are certainly optional for us to correct or not.

Let's add a script block here in above code as below:

    1 <%@ Page Language="VB" AutoEventWireup="true" CodeFile="Default.aspx.vb" Inherits="_Default" %>
    3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    4 <html xmlns="http://www.w3.org/1999/xhtml">
    5 <head runat="server">
    6     <title>Untitled Page</title>
    8 </head>
    9 <body>
   10 <script language ="javascript" type="text/javascript" ></script>
   11     <form id="form1" runat="server">
   12         <asp:ScriptManager ID="ScriptManager1" runat="server" />
   13         <div>
   14         </div>
   15     </form>
   16 </body>
   17 </html>


Now check for accessibility by clicking on validate button


See the warning number 1, it says that we should also provide a no script tag. off course it is necessary that we should provide a no script tag, as if JavaScript is disabled then our code behavior would be disturbed. Similarly for frames we need to add a <noframes> tag and for <object> we should provide a <noobject> tag. Otherwise you better understand what possibly could happen.

This way whenever you produce some code, do check against the checklist, as visual studio.net 2005 and 2008 have awesome support to check for accessibility errors so one should make a habit of validations and rules. Visual studio assists in developing accessible websites to the fullest but we as developers show laziness or sometimes due to deadlines we are in hassle, and we do not care about. But later on we have to pay for extra time as we always get cross browser websites. Let's follow the same example and see how Visual Studio assists us in development. Let's add a table in above code.


Here we can see that we are asked to provide all the information including summary description and other attributes, though we also need to add table headers and captions where necessary to make a table fully accessible. Let's see a fully accessible code with a table below:

    1 <%@ Page Language="VB" AutoEventWireup="true" CodeFile="Default.aspx.vb" Inherits="_Default" %>
    3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    4 <html xmlns="http://www.w3.org/1999/xhtml">
    5 <head runat="server">
    6     <title>Untitled Page</title>
    8 </head>
    9 <body>
   10 <script language ="javascript" type="text/javascript" ></script><noscript></noscript>
   11     <form id="form1" runat="server" >
   12         <asp:ScriptManager ID="ScriptManager1" runat="server" />
   13         <div>
   14             <div style="text-align: left">
   15                 <table border="1" cellpadding="1" cellspacing="1" summary="This is a demo table">
   16                     <caption>
   17                     </caption>
   18                     <thead>
   20                     </thead>
   21                       <tr>
   22                         <th></th>
   23                         <th></th>
   24                         <th></th>
   25                       </tr>
   26                     <tr>
   27                         <td style="width: 100px">
   28                         </td>
   29                         <td style="width: 100px">
   30                         </td>
   31                         <td style="width: 100px">
   32                         </td>
   33                     </tr>
   34                     <tr>
   35                         <td style="width: 100px">
   36                         </td>
   37                         <td style="width: 100px">
   38                         </td>
   39                         <td style="width: 100px">
   40                         </td>
   41                     </tr>
   42                     <tr>
   43                         <td style="width: 100px">
   44                         </td>
   45                         <td style="width: 100px">
   46                         </td>
   47                         <td style="width: 100px">
   48                         </td>
   49                     </tr>
   50                 </table>
   51             </div>
   53         </div>
   54     </form>
   55 </body>
   56 </html>

Click on image to see larger

It is clear that we have reduced the warnings to nine and there are zero errors in the list.

Apart from Visual Studio, you can also check your website for accessibility and other standards on URL below:



Hope this discussion will help the developers to have an idea for how to make the ASP.NET websites accessible and cross browser compatible.

For reference i am providing the checklist provided by W3C

Accessibility Priorities

Each checkpoint has a priority level assigned by the Working Group based on the checkpoint's impact on accessibility.

[Priority 1]
A Web content developer must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in the document. Satisfying this checkpoint is a basic requirement for some groups to be able to use Web documents.

[Priority 2]
A Web content developer should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document. Satisfying this checkpoint will remove significant barriers to accessing Web documents.

[Priority 3]
A Web content developer may address this checkpoint. Otherwise, one or more groups will find it somewhat difficult to access information in the document. Satisfying this checkpoint will improve access to Web documents.

Some checkpoints specify a priority level that may change under certain (indicated) conditions.

Web Site Accesibility: Priority 1 checkpoints

In General (Priority 1) Yes No N/A
1.1 Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ascii art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video.      
2.1 Ensure that all information conveyed with color is also available without color, for example from context or markup.      
4.1 Clearly identify changes in the natural language of a document's text and any text equivalents (e.g., captions).      
6.1 Organize documents so they may be read without style sheets. For example, when an HTML document is rendered without associated style sheets, it must still be possible to read the document.      
6.2 Ensure that equivalents for dynamic content are updated when the dynamic content changes.      
7.1 Until user agents allow users to control flickering, avoid causing the screen to flicker.      
14.1 Use the clearest and simplest language appropriate for a site's content.      
And if you use images and image maps (Priority 1) Yes No N/A
1.2 Provide redundant text links for each active region of a server-side image map.      
9.1 Provide client-side image maps instead of server-side image maps except where the regions cannot be defined with an available geometric shape.      
And if you use tables (Priority 1) Yes No N/A
5.1 For data tables, identify row and column headers.      
5.2 For data tables that have two or more logical levels of row or column headers, use markup to associate data cells and header cells.      
And if you use frames (Priority 1) Yes No N/A
12.1 Title each frame to facilitate frame identification and navigation.      
And if you use applets and scripts (Priority 1) Yes No N/A
6.3 Ensure that pages are usable when scripts, applets, or other programmatic objects are turned off or not supported. If this is not possible, provide equivalent information on an alternative accessible page.      
And if you use multimedia (Priority 1) Yes No N/A
1.3 Until user agents can automatically read aloud the text equivalent of a visual track, provide an auditory description of the important information of the visual track of a multimedia presentation.      
1.4 For any time-based multimedia presentation (e.g., a movie or animation), synchronize equivalent alternatives (e.g., captions or auditory descriptions of the visual track) with the presentation.      
And if all else fails (Priority 1) Yes No N/A
11.4 If, after best efforts, you cannot create an accessible page, provide a link to an alternative page that uses W3C technologies, is accessible, has equivalent information (or functionality), and is updated as often as the inaccessible (original) page.      

Web Site Accessibility - Priority 2 checkpoints

In General (Priority 2) Yes No N/A
2.2 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. [Priority 2 for images, Priority 3 for text].      
3.1 When an appropriate markup language exists, use markup rather than images to convey information.      
3.2 Create documents that validate to published formal grammars.      
3.3 Use style sheets to control layout and presentation.      
3.4 Use relative rather than absolute units in markup language attribute values and style sheet property values.      
3.5 Use header elements to convey document structure and use them according to specification.      
3.6 Mark up lists and list items properly.      
3.7 Mark up quotations. Do not use quotation markup for formatting effects such as indentation.      
6.5 Ensure that dynamic content is accessible or provide an alternative presentation or page.      
7.2 Until user agents allow users to control blinking, avoid causing content to blink (i.e., change presentation at a regular rate, such as turning on and off).      
7.4 Until user agents provide the ability to stop the refresh, do not create periodically auto-refreshing pages.      
7.5 Until user agents provide the ability to stop auto-redirect, do not use markup to redirect pages automatically. Instead, configure the server to perform redirects.      
10.1 Until user agents allow users to turn off spawned windows, do not cause pop-ups or other windows to appear and do not change the current window without informing the user.      
11.1 Use W3C technologies when they are available and appropriate for a task and use the latest versions when supported.      
11.2 Avoid deprecated features of W3C technologies.      
12.3 Divide large blocks of information into more manageable groups where natural and appropriate.      
13.1 Clearly identify the target of each link.      
13.2 Provide metadata to add semantic information to pages and sites.      
13.3 Provide information about the general layout of a site (e.g., a site map or table of contents).      
13.4 Use navigation mechanisms in a consistent manner.      
And if you use tables (Priority 2) Yes No N/A
5.3 Do not use tables for layout unless the table makes sense when linearized. Otherwise, if the table does not make sense, provide an alternative equivalent (which may be a linearized version).      
5.4 If a table is used for layout, do not use any structural markup for the purpose of visual formatting.      
And if you use frames (Priority 2) Yes No N/A
12.2 Describe the purpose of frames and how frames relate to each other if it is not obvious by frame titles alone.      
And if you use forms (Priority 2) Yes No N/A
10.2 Until user agents support explicit associations between labels and form controls, for all form controls with implicitly associated labels, ensure that the label is properly positioned.      
12.4 Associate labels explicitly with their controls.      
And if you use applets and scripts (Priority 2) Yes No N/A
6.4 For scripts and applets, ensure that event handlers are input device-independent.      
7.3 Until user agents allow users to freeze moving content, avoid movement in pages.      
8.1 Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies [Priority 1 if functionality is important and not presented elsewhere, otherwise Priority 2.]      
9.2 Ensure that any element that has its own interface can be operated in a device-independent manner.      
9.3 For scripts, specify logical event handlers rather than device-dependent event handlers.      

Web Site Accessibility - Priority 3 checkpoints

In General (Priority 3) Yes No N/A
4.2 Specify the expansion of each abbreviation or acronym in a document where it first occurs.      
4.3 Identify the primary natural language of a document.      
9.4 Create a logical tab order through links, form controls, and objects.      
9.5 Provide keyboard shortcuts to important links (including those in client-side image maps), form controls, and groups of form controls.      
10.5 Until user agents (including assistive technologies) render adjacent links distinctly, include non-link, printable characters (surrounded by spaces) between adjacent links.      
11.3 Provide information so that users may receive documents according to their preferences (e.g., language, content type, etc.)      
13.5 Provide navigation bars to highlight and give access to the navigation mechanism.      
13.6 Group related links, identify the group (for user agents), and, until user agents do so, provide a way to bypass the group.      
13.7 If search functions are provided, enable different types of searches for different skill levels and preferences.      
13.8 Place distinguishing information at the beginning of headings, paragraphs, lists, etc.      
13.9 Provide information about document collections (i.e., documents comprising multiple pages.).      
13.10 Provide a means to skip over multi-line ASCII art.      
14.2 Supplement text with graphic or auditory presentations where they will facilitate comprehension of the page.      
14.3 Create a style of presentation that is consistent across pages.      
And if you use images and image maps (Priority 3) Yes No N/A
1.5 Until user agents render text equivalents for client-side image map links, provide redundant text links for each active region of a client-side image map.      
And if you use tables (Priority 3) Yes No N/A
5.5 Provide summaries for tables.      
5.6 Provide abbreviations for header labels.      
10.3 Until user agents (including assistive technologies) render side-by-side text correctly, provide a linear text alternative (on the current page or some other) for all tables that lay out text in parallel, word-wrapped columns.      
And if you use forms (Priority 3) Yes No N/A
10.4 Until user agents handle empty controls correctly, include default, place-holding characters in edit boxes and text areas.      


This tutorial is written by Ali Sufyan.

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