function openWindow(url,winwidth,winheight){
	var xpos=window.screen.availWidth/2 - winwidth/2
        var ypos=window.screen.availHeight/2 - winheight/2
        winsettings = 'scrollbars,resizable,status,width=' + winwidth + ',height=' + winheight + ',left=' + xpos + ',top=' + ypos
	window.open(url,'openWindow',winsettings);
}