var popup = new Object()

function getbrowserwidth()
{
    if (navigator.userAgent.indexOf("MSIE") > 0)
    {
        return(document.body.clientWidth);
    }
    else
    {
        return window.outerWidth;
    }
}
function getbrowserheight()
{
	if (navigator.userAgent.indexOf("MSIE") > 0)
    {
        return(document.body.clientHeight);
	} 
    else
	{
		return(window.outerHeight);
	}
}
function CenterPopup(URL, width, height)
{
    // get center of browser window
    var X = getbrowserwidth() / 2
    var Y = getbrowserheight() / 2
                    	
    popup = window.open(URL, 'PopUp', 
		'scrollbars=yes ' +
		'resizable=yes ' +
		'width=' + width + ' ' +
		'height=' + height + ' ' +
		'top=' + (window.screenTop + (Y - (height/2))) + ' ' +
		'left=' + (window.screenLeft + (X - (width/2))) 
		)
                    	
    popup.focus()
}