var eventTarget, eventTargetParent;

function addListener (obj, targetEvent, action, capture) {
	obj.addEventListener ? obj.addEventListener(targetEvent, action, capture) : obj.attachEvent('on' + targetEvent, action);
}

function removeListener (obj, targetEvent, action, capture) {
	obj.removeEventListener ? obj.removeEventListener(targetEvent, action, capture) : obj.removeEventListener('on' + targetEvent, action);
}

function setGlobalEventVars (event) {
	event.target ? eventTarget = event.target : eventTarget = event.srcElement;
	eventTargetParent = eventTarget.parentNode;	
}

function swapImgSrc (event) {
	
	setGlobalEventVars(event);
		
	if (eventTarget.nodeName == 'IMG') {
	
		var src1 = '_on'
		var src2 = '_off'
	
		if (event.type == 'mouseover' || event.type == 'onmouseover') {
			src1 = '_off';
			src2 = '_on'
		} 
		
		eventTarget.setAttribute('src', eventTarget.getAttribute('src').replace(src1, src2));
	
	}
}


function init() {

	var targetArray = new Array('topNav', 'sideNav', 'siteLogo', 'bottomNav');

	
	for (var x = 0; x < targetArray.length; x++) {
		
		var target = targetArray[x];
		var currentLocation = window.location.toString().split('/');
		
		if (target == 'topNav') {
			currentLocation = currentLocation[3];
		}
		
		if (target == 'sideNav') {
			currentLocation = currentLocation[currentLocation.length - 1];
		} 
				
		if (document.getElementById(target)) {
		
			var imgList = document.getElementById(target).getElementsByTagName('IMG');
			
			for (var y = 0; y < imgList.length; y++) {
			
				var pattern = new RegExp(currentLocation);
				var result = pattern.exec(imgList[y].parentNode.getAttribute('href'));
				
				if (result && x < 2) {
					imgList[y].setAttribute('src', imgList[y].getAttribute('src').replace('_off.', '_on.'));
					
				} else {
				
					addListener(imgList[y], 'mouseover', swapImgSrc, false)
					addListener(imgList[y], 'mouseout', swapImgSrc, false)
				}
			}
		}
	}
}