JavaScript Issues ,use of device independent event handler,JavaScript alternatives etc.

1. Savitribai Phule Pune University

2.  developed by Netscape Corporation.
 Similar to Java , but not stand-alone language.
 When the browser reads JavaScript code within
your HTML document, it processes the code,
then displays any output within the web page.
 The computer reading the JavaScript must have
a JavaScript interpreter
Savitribai Phule Pune University

3.  Navigation- Inability or difficulty navigating using a
keyboard or assistive technology.
 Hidden content- Presentation of content or
functionality that is not accessible to assistive
technologies.
 User control- Lack of user control over automated content
changes.
 Confusion/Disorientation- Altering or disabling the
normal functionality of the user agent (browser) or triggering
events that the user may not be aware of.
Savitribai Phule Pune University

4.  The <script> element can contain
JavaScript code directly:
<script type="text/javascript">
<!-- function doit(); -->
</script>
 or can open an external JavaScript (.js)
file:
<script type="text/javascript"
src="scripts.js">
Savitribai Phule Pune University

5.  onMouseOver and onMouseOut -
Example-
<a href="productlinks.htm"
onmouseover="SlideOutMenu();"
onmouseout="SlideInMenu();">Products</a>
 onFocus and onBlur -
Example-
<input id="fname" type="text" onfocus="alert('Enter
your first name only');" />
 onClick and onDblClick -
Example-
<a href="page.htm" onclick="return confirm('Are you
sure you want to view this page?');">View this onClick
example</a>
Savitribai Phule Pune University

6.  onChange and onSelect -
Example-
<form action="page.htm" onsubmit="return false;">
<p><label for="selectPage2">Go to:</label>
<select name="selectPage2" id="selectPage2">
<option value="">Select a page:</option>
<option value="page.htm">Page 1</option>
<option value="page.htm">Page 2</option>
<option value="page.htm">Page 3</option>
</select>
<input type="button" value="Go!"
onclick="goto_URL(this.form.selectPage2);" />
</p>
</form>
Savitribai Phule Pune University

7.  Combination of CSS and Javascript.
 When DHTML is used, two items must be evaluated
to determine its impact on accessibility:
1. Is the event used to trigger a change device
independent?
2. Is the DHTML content or functionality itself
accessible? If assistive technologies cannot
adequately access DHTML triggered content or
functionality, then it is not fully accessible.
Savitribai Phule Pune University

8.  Using Pure CSS –
eg. To hide content, use either
visibility:hidden or display:none.
 Server-side Processing-
 Using the <noscript> Element –
The <noscript> content should ideally
contain the equivalent content or functionality
that is provided by the script.
Savitribai Phule Pune University

9.  JavaScript allows developers to add increased
interaction, information processing, and control in
web-based content.
 JavaScript can also cause accessibility problems
by
1. limiting navigation using a keyboard or
assistive technology,
2. presenting content or functionality that is
not accessible to assistive
technologies,
3. limiting user control over automated content
changes, and
4. modifying the normal functionality of the
browser.
Savitribai Phule Pune University

10. Savitribai Phule Pune University