function getPageSize2 () 
{
	        
	var xScroll, yScroll;
		
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = window.innerWidth + window.scrollMaxX;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
		
	var windowWidth, windowHeight;
		
	if (self.innerHeight) 
	{	// all except Explorer
		if(document.documentElement.clientWidth)
		{
			windowWidth = document.documentElement.clientWidth; 
		}
		else
		{
			windowWidth = self.innerWidth;
		}
		windowHeight = self.innerHeight;
	} 
	else if (document.documentElement && document.documentElement.clientHeight) 
	{ // Explorer 6 Strict Mode
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	}
	else if (document.body) 
	{ // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}	
		
	// for small pages with total height less then height of the viewport
	if(yScroll < windowHeight)
	{
		pageHeight = windowHeight;
	} 
	else
	{ 
		pageHeight = yScroll;
	}
	
	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth)
	{	
		pageWidth = xScroll;		
	}
	else 
	{
		pageWidth = windowWidth;
	}

	return [pageWidth,pageHeight];
	//return [810, 540];
}

function inicio(id, w, h)
{
	var arrayPageSize = this.getPageSize2();
    //$('overlay').setStyle({ width: arrayPageSize[0] + 'px', height: arrayPageSize[1] + 'px' });
	var altura = (arrayPageSize[1]-h)/2;
	var ancho = (arrayPageSize[0]-w)/2;
	if (altura<0) altura=0;
	if (ancho<0) ancho=0;
	
	obj = document.getElementById(id);
    obj.style.visibility = "hidden";
	obj.style.top = altura+"px";
	obj.style.left = ancho+"px";
	obj.style.visibility = "visible";	
}