//Thanks to http://www.webdevfaqs.com for the JavaScript
function openwin(url, width, height) {

var name = "popup"; // popup name
var width = width; // popup width
var height = height; // popup height
var left = (screen.width - width) / 2 ;
var top = (screen.height - height) / 2;
var windowproperties = "width="+ width +",height="+ height +",left="+ left +",top="+ top +",scrollbars=0";
window.open(url, name, windowproperties);
}