function showPopupHowtobuy(id)
  {
	fillOverlay();
	ele = document.getElementById(id);
	ele.style.position="absolute";
	ele.style.left= (screen.width-450)/2;
	ele.style.top=700;
	ele.style.display="block";
  }
 function showPopup(id)
  {
	fillOverlay();
	ele = document.getElementById(id);
	ele.style.position="absolute";
	ele.style.left= (screen.width-450)/2;
	ele.style.top=(screen.height-700)/2;
	ele.style.display="block";
  }

  function closePopup(id)
  {
	ele = document.getElementById(id);
	ele.style.display="none";
	hideOverlay();
	window.location.href=unescape(window.location.pathname);
  }

function fillOverlay() 
{
		var overlay = document.createElement("div");
		var pageSize = getPageSize();
		//alert(pageSize[0]);alert(pageSize[1]);
		overlay.style.width = pageSize[0] +"px";
		overlay.style.height = pageSize[1] +"px";
		overlay.id = 'overlay';
		overlay.className='overlay';
		document.body.appendChild(overlay);
}
function hideOverlay() 
{
		var el = document.getElementById('overlay');
		if (el) {
			el.parentNode.removeChild(el);
			}
}
 function getPageSize() 
 {
		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;
		}
		if(yScroll < windowHeight){
			pageHeight = windowHeight;
		} else {
			pageHeight = yScroll;
		}
		if(xScroll < windowWidth){
			pageWidth = xScroll;
		} else {
			pageWidth = windowWidth;
		}
		arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight)
		return arrayPageSize;
	}