function getCookie(name) {
var matches = document.cookie.match(new RegExp(
"(?:^|; )" + name.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g, '\\$1') + "=([^;]*)"
));
return matches ? decodeURIComponent(matches[1]) : undefined;
}
if (getCookie('CityId') == 781) {
// do stuff
}