System Specific Usability Issues

The Usability of websites differs from the type of websites. The main type of websites can be:

1) E - commerce and Shopping Cart
2) Travel websites
3) Blogs
4) Information websites etc.

Along with the other Issues, there are few more usability issues which needs to be taken care of while doing usability for a website.

Text Presentation

Specific guidelines for text presentation may be summarized as follows.

# Use sans serif fonts like Arial or Helvetica.
#Strive for 14-point font size for body text and 18–24 point for headers. Provide a
#Text sizing option on your page.
#Use boldface; avoid italics.
#Use upper and lower case; avoid using all capitals.
#Use left-justified text; avoid centered or full justification.
#Increase leading (the space between lines of text).
#Keep line lengths between 50 and 65 characters.
#Use headings and subheadings.
#Use negative contrast (black text on white ground).
#Use active white space.
#Place text on unpatterned backgrounds.
#Use consistent placement of page elements.
#Increase the size of peripheral elements.
#Separate the steps of a procedure using numbers or bullets.
#Use a minimum number of hypertext links in a single line of text.
#Avoid multicolumn format or frames.
#Avoid flashing or blinking text.

Javascript

Javascript is one of the most popular scripting languages for web development. In addition to libraries of Javascript code available online, two of the most popular web development tools, FrontPage and Dreamweaver, include easy-to-access code snippets that add little "extras" to web pages. Developers should use caution when deciding to include Javascript or other scripting elements on their pages. Here are a few of the most popular uses for Javascript and some of the accessibility issues to consider:

onClick – The onClick event handler is triggered when the user clicks once on a particular item. It is commonly used on links and button elements and, used in connection with these elements; it works well with screen readers. If clicking on the element associated with the onClick event handler triggers a function or performs some other action, developers should ensure that the context makes that fact clear to all users. Do not use the onClick event handlers for form elements that include several options (e.g. select lists, radio buttons, checkboxes) unless absolutely necessary.

onMouseOver and onMouseOut – These two event handlers are very popular on many web sites. For instance, so-called rollover gif's, which swap images on a web page when the mouse passes over an image, typically use both of these event handlers. These event handlers neither can be accessed by the mouse nor interfere with accessibility – a screen reader simply bypasses them entirely. Accordingly, web designers who use these event handlers should be careful to duplicate the information (if any) provided by these event handlers through other means.

OnChange – This event handler is very commonly used for triggering JavaScript functions based on a selection from within a tag. Surprisingly, it presents tremendous accessibility problems for many commonly used screen readers and should be avoided. Instead, web developers should use the onClick event handler (associated with a link or button that is adjacent to a tag) to accomplish the same functions.


Lists

Lists are commonly found on websites. These may be lists of, for example, people, drugs, theaters, or restaurants.
Each list should be clearly introduced and have a descriptive title. A list should be formatted so that it can be easily scanned. The order of items in the list should be done to maximize user performance, which usually means that the most important items are placed toward the top of the list. If a numbered list is used, start the numbering at “one,” not “zero.” Generally only the first letter of the first word is capitalized, unless a word that is usually capitalized is shown in the list.

1) Arrange lists and tasks in an order that best facilitates efficient and successful user performance.
Where no obvious order applies, organize lists alphabetically or numerically. Keep in mind that it is the user’s logic that should prevail rather than the designer ’s logic.

2) Display a series of related items in a vertical list rather than as continuous text.

3) Provide an introductory heading (i.e., word or phrase) at the top of each list.

4) Place a list’s most important items at the top.

5) Capitalize the first letter of only the first word of a list item, a list box item, check box labels, and radio button labels.

6) Use bullet lists to present items of equal status or value, and numbered lists if a particular order to the items is warranted.