JavaScript: Display a sized modal popup

// ***
// Displays a sized modal popup
// ***
function popUpModalSized(URL,width,height)
{
xwidth = width;
xheight = height;
xleft = (screen.width - width ) / 2;
xtop = (screen.height - height ) / 2;
title = '';
windowOptions = 'dialogWidth:' + xwidth + 'px; dialogHeight:' + xheight + 'px; dialogLeft:' + xleft + 'px; dialogTop:' + xtop + 'px; edge: Raised; center: yes; resizable: no; maximize:no; minimize:yes; status: no; scroll: no; help: no';
var rc = window.showModalDialog(URL,title,windowOptions);
}