function preloadImages(){
	for(i=0;i<imgArray.length;i++){
		newImage[i] = new Image();
		newImage[i].src = imgArray[i];
	}
}

function showMenu(tabId){
	var tempId = document.getElementById(tabId);
	var tempImage = document.getElementById(tabId+"Image");
	tempImage.src = "images/"+tabId+"_over.jpg";
	tempId.className = "navOn";	
}

function hideMenu(tabId){
	var tempId = document.getElementById(tabId);
	var tempImage = document.getElementById(tabId+"Image");
	tempImage.src = "images/"+tabId+"_out.jpg";
	tempId.className = "navOff";	
}