function pageLoad() {
    setHeights();
    setupNavImages();
    preloadImages();
}

function setHeights() {
    var elements = document.getElementById("page").getElementsByTagName("div");
    for (var i=0; i<=elements.length; i++) {
        if (!elements[i] || elements[i].className.indexOf("highlight") == -1) break;
        else {
            elements[i].style.height = getContainerHeight() - 140 + "px";  
        }
    }
}

function getContainerHeight() {
    if (window.opera) return document.body.clientHeight;
    if (navigator.userAgent.indexOf('Safari') > -1) return self.innerHeight;
    else return document.documentElement.clientHeight;
}

function preloadImages() {
    var imageCollection = new Array();
    var imageObj = new Image();
    
    imageCollection[0] = "../images/nav/home-hover.png";
    imageCollection[1] = "../images/nav/who-hover.png";
    imageCollection[2] = "../images/nav/what-hover.png";
    imageCollection[3] = "../images/nav/why-hover.png";
    imageCollection[4] = "../images/nav/gallery-hover.png";
    imageCollection[5] = "../images/nav/news-hover.png";
    imageCollection[6] = "../images/nav/contact-hover.png";
    
    for (var i=0; i<=imageCollection.length; i++) {
        imageObj.src = imageCollection[i];
    }
}

function setupNavImages() {
    var navElements = document.getElementById("nav").getElementsByTagName("img");
    for (var i = 0; i < navElements.length; i++) {//alert(navElements[i].className);
        if (navElements[i].className != "active") {
            addEvent(navElements[i], "mouseover", navOver, true);
            addEvent(navElements[i], "mouseout", navOut, true);
        }
    }
}

function navOver(e) {
    var source = getEvent(e);
    var imgSrc = source.src;
    if (imgSrc.indexOf("-hover") == -1) {
        source.src = imgSrc.substr(0, imgSrc.lastIndexOf(".")) + "-hover" + imgSrc.substr(imgSrc.lastIndexOf("."), imgSrc.length)
    }
}

function navOut(e) {
    var source = getEvent(e);
    var imgSrc = source.src;
    if (imgSrc.indexOf("-hover") > -1) {
        source.src = imgSrc.substr(0, imgSrc.lastIndexOf("-hover")) + imgSrc.substr(imgSrc.lastIndexOf("."), imgSrc.length)
    }
}


function getEvent(e) {
    var source;
	if (!e) var e = window.event;
	if (e.target) source = e.target;
	else if (e.srcElement) source = e.srcElement;
	if (source.nodeType == 3) source = targ.parentNode;
	e.cancelBubble = true;
    return source;
}

function addEvent(target,evt,callback,useCapture){
	if (!useCapture) useCapture = false;
	if (target.addEventListener){
		target.addEventListener(evt,callback,useCapture);
	} else if (target.attachEvent) {
	    target.attachEvent("on"+evt,callback);
	} else {
	    target["on"+evt] = callback;
	}
} 

addEvent(window, "load", pageLoad, false);