jQuery Tools is a collection of user interface plugins that allow you to achieve effects like tabbed content, lightbox-style overlays, and tooltips. These effects are already built into the web system, but they're implemented through the editing of page HTML.
jQuery Tools allow you to separate content into neatly tabbed sections. This allows users to access new content without loading entirely new pages, which saves on bandwidth, speeding up browsing. If a person is using a screen reader or has javascript enabled, all content is shown.
