var currentOver;
/*
 * Function switches the given elements parent class
 * activating the on state of the element in the top
 * navigation.
 * 
 * @param {Object} element - Anchor Link
 */
function showOver(element) {
	if(currentOver == element)
		return;
	else if(currentOver) {
		removeOver(currentOver);
	}
	element.parentNode.className = 'header_link_over';
	currentOver = element;
}
/*
 * Function adds an off state class from the given 
 * elements parent class. 
 * 
 * @param {Object} element - Anchor Link
 */
function removeOver(element) {
	if(currentOver == element) {
		element.parentNode.className = 'header_link';
		currentOver = null;
	}
}