// manager function to set the current state of main nav link images
function nav_setcurrent(){
	// turn on selected states for mainnav
	var currentHref = window.location.href;
	// products
	var lnkProducts = document.getElementById('lnkProducts');
	if(currentHref.indexOf('/products/') > -1){nav_turnoffrollover(lnkProducts);}
	// how_to
	var lnkHowto = document.getElementById('lnkHowto');
	if(currentHref.indexOf('/how_to/') > -1){nav_turnoffrollover(lnkHowto);}
	// contact
	var lnkContact = document.getElementById('lnkContact');
	if(currentHref.indexOf('/contact/') > -1){nav_turnoffrollover(lnkContact);}
	
}
// helper function to remove class='imgover' from image and set <img> src to over image
function nav_turnoffrollover(lnkNavItem){
	// get the nav image inside of <a id="lnkProducts">
	var elImg = lnkNavItem.firstChild;
	//while (elImg.nodeName.toLowerCase() != 'img' && elImg.className != 'imgover'){
	while (elImg.nodeName.toLowerCase() != 'img'){
		elImg = elImg.nextSibling;
	}
	// remove imgover class and change source to over
	removeCssClass(elImg, 'imgover');
	var src = elImg.getAttribute('src');
	var ftype = src.substring(src.lastIndexOf('.'), src.length);
	var hsrc = src.replace(ftype, '_over' + ftype);
	elImg.setAttribute('src', hsrc);
}

addEvent(window, 'load', nav_setcurrent);