fire_custom_event.js

function fireCustomEvent(eventType) {
    if ( document.dispatchEvent ) { // DOM browser
        var e = document.createEvent("UIEvents");
        e.initEvent(eventType, false, false);
        document.dispatchEvent(e);
    } else if ( document.attachEvent ) { // IE
        if ( !document.documentElement[eventType] )
            document.documentElement[eventType] = 1;
        else
            document.documentElement[eventType] += 1;
    }
};

$.listenCustomEvent = function(eventType, callback) {
    $(document).on(eventType, callback);
    $(document.documentElement).on('propertychange', function(e) {
        if (e.originalEvent.propertyName == eventType)
            callback();
    });
};

// Use case
$.listenCustomEvent('wa-test', function() {
    alert('It\'s worked!');
});

fireCustomEvent('wa-test');