function openWindow(url, noparams) 
{
  var w = screen.width;
 	var y = screen.height;
	if (w<=600) {
	 var dimx = 540;
	 var dimy = 280;
	}
	else if (w<=800) {
	 var dimx = 640;
	 var dimy = 380;
	}
	else if (w>800) {
 	 var dimx = 800;
	 var dimy = 500;
	}
	var leftPos=(w-dimx)/2;
	var topPos=(y-dimy)/2;
	if (!arguments[1])
 	  params = 'scrollbars=1,resizable=1,location=1,directories=1,menubar=1,'
	else if (arguments[1] && arguments != '' && typeof(arguments[1]) != 'boolean'){
 	  params = arguments[1]+',';
	}
	else
	  params = ''
	
	window.open(url,'',params + 'width='+dimx+',height='+dimy+',top='+topPos+',left='+leftPos);
}