window.onload = prep;

function prep(){
	if (document.getElementById('navigation')){
		var imgs = document.getElementsByTagName("img");
		var img_num = imgs.length;
		for (var a=0; a < img_num; a++){
			if ( imgs[a].className == 'tab' ){
				imgs[a].onmouseover = function(){
					return tabOn(this)
				}
				imgs[a].onmouseout = function(){
					return tabOff(this)
				}
				
			}
		}
	}//if document etc
	
	preLoad()
}

function preLoad()
{
	var images = new Array('ov_07.jpg', 'ov_09.jpg', 'ov_11.jpg', 'ov_13.jpg', 'ov_15.jpg', 'ov_17.jpg');
	var image_num = images.length;
	var loaded = new Array();
	for ( var x=0; x < image_num; x++ ){
		loaded[x] = new Image();
		loaded[x].src = 'images/'+images[x]+'';
	}
}

function tabOn(img)
{
	
	var source = img.getAttribute('src');
	var urlitems = source.split('/');
	
	var filename = urlitems[urlitems.length - 1];
	//in_09.jpg
	var nameitems = filename.split('.');
	
	var new_filename = 'images/'+filename.replace('in_', 'ov_');

	img.setAttribute('src', new_filename);
}

function tabOff(img)
{
	var source = img.getAttribute('src');
	var urlitems = source.split('/');
	
	var filename = urlitems[urlitems.length - 1];
	
	var new_filename = 'images/'+filename.replace('ov_', 'in_');

	img.setAttribute('src', new_filename);
}