function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			oldonload();
			func();
		}
	}
}

function loadingPage() {
	var loadingImage = '_img/loading.gif';
	var overlayImage = '_img/overlay.png';
	
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();
	
	var objBody = document.getElementsByTagName("body").item(0);
	var objOverlay = document.createElement("div");
	objOverlay.setAttribute('id','overlay');
	objOverlay.style.display = 'none';
	objOverlay.style.position = 'absolute';
	objOverlay.style.top = '0';
	objOverlay.style.left = '0';
	objOverlay.style.zIndex = '100000';
	objOverlay.style.width = '100%';
	objBody.insertBefore(objOverlay, objBody.firstChild);
	
	
	var overlayPreloader = new Image();
	overlayPreloader.src = overlayImage;
	var imgPreloader = new Image();
	imgPreloader.src = loadingImage;
	
	imgPreloader.onload=function(){	
		var objLoadingImage = document.createElement("img");
		objLoadingImage.src = loadingImage;
		objLoadingImage.setAttribute('id','loadingImage');
		objLoadingImage.style.position = 'absolute';
		objLoadingImage.style.zIndex = '150';
		objOverlay.appendChild(objLoadingImage);
		
		var objLoadingImage = document.getElementById('loadingImage');
		objLoadingImage.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - objLoadingImage.height) / 2) + 'px');
		objLoadingImage.style.left = (((arrayPageSize[0] - 20 - objLoadingImage.width) / 2) + 'px');
		objLoadingImage.style.display = 'block';
	
		imgPreloader.onload=function(){};
		return false;
	}
	
	var objOverlay = document.getElementById('overlay');
	objOverlay.style.height = (arrayPageSize[1] + 'px');
	objOverlay.style.display = 'block';
}

function getPageScroll(){

	var yScroll;

	if (self.pageYOffset) {
		yScroll = self.pageYOffset;
	} else if (document.documentElement && document.documentElement.scrollTop){
		yScroll = document.documentElement.scrollTop;
	} else if (document.body) {
		yScroll = document.body.scrollTop;
	}

	arrayPageScroll = new Array('',yScroll) 
	return arrayPageScroll;
}

function getPageSize(){
	
	var xScroll, yScroll;
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = document.body.scrollWidth;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else {
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
	
	var windowWidth, windowHeight;
	if (self.innerHeight) {
		windowWidth = self.innerWidth;
		windowHeight = self.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) {
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	} else if (document.body) { // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}	
	
	if(yScroll < windowHeight){
		pageHeight = windowHeight;
	} else { 
		pageHeight = yScroll;
	}

	if(xScroll < windowWidth){	
		pageWidth = windowWidth;
	} else {
		pageWidth = xScroll;
	}


	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
}

function loadingHide(){
	var objLoadingImage = document.getElementById('loadingImage');
	var objOverlay = document.getElementById('overlay');
	
	objOverlay.style.display = 'none';
	objLoadingImage.style.display = 'none';
	
	return false;
}
addLoadEvent(loadingHide);