Collapsible lists in JavaScript

Long nested lists on web pages can be difficult to understand, especially if the visitor must scroll to see the entire list. The tree view, a user interface widget that displays hierarchical data as nested lists, solves this problem by making lists collapsible and expandable; a list can be opened by or closed by clicking on its parent list item. CollapsibleLists is a JavaScript object that turns a normal HTML list into a tree view. In the example below, click on the items with plus and minus icons to expand and collapse their lists; in this example the top level deliberately cannot be collapsed.

Please Follow the below link
http://code.stephenmorley.org/javascript/collapsible-lists/