function popup( strUrl, strWindow, width, height) {
    	xposition=0; yposition=0;
    	if (parseInt(navigator.appVersion) >= 4){
        	xposition = (screen.width - width) / 2;
        	yposition = (screen.height - height) / 2;
	    }
    	args = "width=" + width + "," + "height=" + height + "," + "location=0," + "menubar=0," + "resizable=1," + "scrollbars=1," + "status=0," + "titlebar=0," + "toolbar=0," + "hotkeys=0," + "screenx=" + xposition + "," + "screeny=" + yposition + "," + "left=" + xposition + "," + "top=" + yposition;           
	    var newWin = window.open( strUrl, strWindow ,args );
	    newWin.focus();
	}