This page demonstrates how to prevent an event from triggering the default action by returning false
The following table has two cells, one (the left) with an onclick event handler, one without.
The table itself also has an onclick event handler, and the table is embedded into a link to the CS home page.
The left cell's event handler does not return false:
The left cell's event handler in the following table does return false. Apart from that, the tables are identical: