// hanna_nav.js

// onload events
window.onload = monitor;
//window.onload = preloadImages();

var preloadFlag = false;

function showNav(id) {
	if (element = document.getElementById(id)) {
		if (containsHTML(element)) element.style.display = 'block';
	}
}

function hideNav(id) {
	if (element = document.getElementById(id)) {
		element.style.display = 'none';
	}
}

function hover(obj) {
	orig = obj.childNodes[0].src; // original image src
	noExt = orig.substr(0,orig.indexOf('.gif')); // remove file extention
	obj.childNodes[0].src = noExt + '_o.gif'; // set to new src
}

function unHover(obj) {
	orig = obj.childNodes[0].src; // original image src
	noExt = orig.substr(0,orig.indexOf('_o.gif')); // remove file extention etc
	obj.childNodes[0].src = noExt + '.gif'; // set to new src
}

function monitor() {
	
	// Home sub-nav
	if (document.getElementById('about_nav_menu')) {
		document.getElementById('about_nav_menu').onmouseover = function () {
			showNav('about_nav_menu');
		}
		document.getElementById('about_nav_menu').onmouseout = function () {
			hideNav('about_nav_menu');
		}
	}
	
	// Products sub-nav
	if (document.getElementById('product_nav_menu')) {
		document.getElementById('product_nav_menu').onmouseover = function () {
			showNav('product_nav_menu');
		}
		document.getElementById('product_nav_menu').onmouseout = function () {
			hideNav('product_nav_menu');
		}
	}
	
	// Support sub-nav
	if (document.getElementById('support_nav_menu')) {
		document.getElementById('support_nav_menu').onmouseover = function () {
			showNav('support_nav_menu');
		}
		document.getElementById('support_nav_menu').onmouseout = function () {
			hideNav('support_nav_menu');
		}
	}
	
	// Calibration sub-nav
	if (document.getElementById('library_nav_menu')) {
		document.getElementById('library_nav_menu').onmouseover = function () {
			showNav('library_nav_menu');
		}
		document.getElementById('library_nav_menu').onmouseout = function () {
			hideNav('library_nav_menu');
		}
	}
	
	// Applications sub-nav
	if (document.getElementById('applications_nav_menu')) {
		document.getElementById('applications_nav_menu').onmouseover = function () {
			showNav('applications_nav_menu');
		}
		document.getElementById('applications_nav_menu').onmouseout = function () {
			hideNav('applications_nav_menu');
		}
	}
	
	// Distributors sub-nav
	if (document.getElementById('distributors_nav_menu')) {
		document.getElementById('distributors_nav_menu').onmouseover = function () {
			showNav('distributors_nav_menu');
		}
		document.getElementById('distributors_nav_menu').onmouseout = function () {
			hideNav('distributors_nav_menu');
		}
	}
    
    // Online Store Button
    if (document.getElementById('store_nav')) {
		document.getElementById('store_nav').onmouseover = function () {
			showNav('store_nav');
		}
		document.getElementById('store_nav').onmouseout = function () {
			hideNav('store_nav');
		}
	}
}

function containsHTML(obj) {
	if (trim(obj.innerHTML) == '') return false;
	return true;
}

function trim(stringToTrim) {
	return stringToTrim.replace(/^\s+|\s+$/g,"");
}