// JavaScript Document
function popup (url, largura, altura) {

	var x = (screen.width - largura) / 2;
	var y = (screen.height - altura) / 2;

	var popup = window.open(url, "popup", "toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, dependent, height=" + altura + ", width=" + largura + ", left=" + x + ", top=" + y);

	if (parseInt (navigator.appVersion)>=4)
		popup.window.focus()

}