var pWindowWidth = 1100;
var pWindowHeight = 680;

function center() {
var cen = 'width=' + pWindowWidth;
cen += ',';
cen += 'height=' + pWindowHeight;
cen += ',';

var cenw = (screen.width / 2) - (pWindowWidth / 2);
var cenh = (screen.height / 2) - (pWindowHeight / 2);
if (navigator.userAgent.indexOf ('MSIE') != -1) {
cen += 'left=' + cenw;
cen +=',';
cen += 'top=' + cenh;
} else if (navigator.userAgent.indexOf ('Mozilla') != -1) {
cen += 'screenX=' + cenw;
cen += ',';
cen += 'screenY=' + cenh;
}
window.open('http://www.city.kobe.jp/cityoffice/06/015/design/catalog/catalog.html','pop',cen);
}