var nav_img = new Array();
function btn_on(id) { document.getElementById(id).src = nav_img['button-'+id+'-over'].src; }
function btn_off(id){ document.getElementById(id).src = nav_img['button-'+id].src;      }

//Preloads All Menus
function btn_preload() {
	path = '_images/';
	images = new Array('home', 'aboutus', 'services', 'contact', 'ourapproach', 'team');
	for (n=0; n<images.length; n++){
		nav_img['button-'+images[n]+''] = new Image; nav_img['button-'+images[n]+''].src = path+'button-'+images[n]+'.gif';
		nav_img['button-'+images[n]+'-over'] = new Image; nav_img['button-'+images[n]+'-over'].src = path+'button-'+images[n]+'-over.gif';
	}
}
btn_preload();