function popup(strUrl, intWidth, intHeight) {

	if(intWidth == null)
		intWidth = screen.availWidth - 500;
	if(intHeight == null)
		intHeight = screen.availHeight - 600;

	var intX = (screen.availWidth / 2) - (intWidth / 2);
    var intY = (screen.availHeight / 2) - (intHeight / 2);

    window.open(strUrl, 'PopUp', 'width = ' + intWidth +', height = ' + intHeight +', left=' + intX + ', top = '+ intY + ', screenX = ' + intX + ', screenY=' + intY + ', scrollbars=yes');
}