// JavaScript Document
var nav_bar = document.getElementById( "mainNav" );
var menu_items = nav_bar.getElementsByTagName( "IMG" );
for( var i = 0; i < menu_items.length; i++ )
{
	menu_items[ i ].onmouseover = function()
	{
		this.src = this.src.replace( "_normal", "_over" );	
	}
	
	menu_items[ i ].onmouseout = function()
	{
		this.src = this.src.replace( "_over", "_normal" );
	}
}