pushstate listener to grab when IS changes URL

ps.js

function pushStateListener() {
    var pushState = history.pushState;
    history.pushState = function() {
        pushState.apply(history, arguments);
        $(window).trigger('pushState');
    };

    $(window).on('pushState', function() {
        alert(String(window.location).match(/.+\/(\d+)(?=\/$)/)[1]); 
//Returns page number
    });
}
pushStateListener();