function pageWidth() {
  return window.innerWidth != null ? window.innerWidth : document.documentElement && document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body != null ? document.body.clientWidth : null;
}

// calculate the current window height //
function pageHeight() {
  return window.innerHeight != null? window.innerHeight : document.documentElement && document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body != null? document.body.clientHeight : null;
}

// calculate the current window vertical offset //
function topPosition() {
  return typeof window.pageYOffset != 'undefined' ? window.pageYOffset : document.documentElement && document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop ? document.body.scrollTop : 0;
}

// calculate the position starting at the left of the window //
function leftPosition() {
  return typeof window.pageXOffset != 'undefined' ? window.pageXOffset : document.documentElement && document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft ? document.body.scrollLeft : 0;
}

function setPosition(containerId)
{
	var dialog = document.getElementById(containerId);
	var width = pageWidth();
	var height = pageHeight();
	var left = leftPosition();
	var top = topPosition();
	var dialogwidth = dialog.offsetWidth;
	var dialogheight = dialog.offsetHeight;
	var topposition = top + (height / 5) - (dialogheight / 3);
	var leftposition = left + (width / 2) - (dialogwidth / 2);
	//alert(leftposition)
	dialog.style.top = topposition + "px";
  	dialog.style.left = leftposition + "px";
		
}