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Buttons
When using a div or span as a button - add roll="button" attribute to the tag. http://www.w3.org/WAI/PF/aria/roles#role_definitions
Consider using some of the other role tags.
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When selecting a set of elements, where possible specify an id first to narrow the DOM search tree. http://www.artzstudio.com/2009/04/jquery-performance-rules/