Web Accessability - "I hear you knocking...but you can't come in"

"I hear you knocking
But you can't come in
I hear you knocking
Go back where you been"

This 1970 Dave Edmunds Billboard hit really sums up accessibility issues as they relate to the web. Website designers who choose to create pages that lack accessibility are sending this very message to individuals with audio, visual & mobile disabilities to name a few. Careful consideration should be taken when designing for those who use tools such as screen readers, braille terminals and speech recognition to utilize the web.

Wikipedia defines web accessibility as "the inclusive practice of making websites usable by people of all abilities and disabilities." Some of the most common accessibility issues include:

• Invisible content - content with a display:none or visibility:hidden in the CSS
  
• Missing alt tags - Images that do not display should still show a descriptive text so that users have an indication of what is missing
  
• Event handlers - events like onclick or onmouseover should not require a mouse or keyboard
  
• Words displayed as images instead of text - once zoomed in, these images will appear pixelated while text will remain crisp.