JS events -- original https://github.com/jeromeetienne/microevent.js with augmentations from https://github.com/jeromeetienne/microevent.js/network

MicroEvent.js

var MicroEvent        = function(){};
MicroEvent.prototype        = {
        bind        : function(event, fct){
                this._events = this._events || {};
                this._events[event] = this._events[event]        || [];
                this._events[event].push(fct);
        },
        once: function(event, fct){
                var wrapped = function() {
                        this.unbind(event, fct);
                        this.unbind(event, wrapped);
                }
                this.bind(event, fct);
                this.bind(event, wrapped);
        },
        unbind        : function(event, fct){
                this._events = this._events || {};
                if( event in this._events === false  )        return;
                this._events[event].splice(this._events[event].indexOf(fct), 1);
        },
        trigger        : function(event /* , args... */){
                this._events = this._events || {};
                if( event in this._events === false  )        return;
                for(var i = 0; i < this._events[event].length; i++){
                        this._events[event][i].apply(this, Array.prototype.slice.call(arguments, 1));
                }
        }
};

/**
 * mixin will delegate all MicroEvent.js function in the destination object
 *
 * - require('MicroEvent').mixin(Foobar) will make Foobar able to use MicroEvent
 *
 * @param {Object} the object which will support MicroEvent
*/
MicroEvent.mixin        = function(destObject){
        var props        = ['bind', 'once', 'unbind', 'trigger'];
        for(var i = 0; i < props.length; i ++){
                if( typeof destObject === 'function' ){
                        destObject.prototype[props[i]]        = MicroEvent.prototype[props[i]];
                }else{
                        destObject[props[i]] = MicroEvent.prototype[props[i]];
                }
        }
}

// Add some method aliases.
MicroEvent.prototype.on = MicroEvent.prototype.bind;
MicroEvent.prototype.off = MicroEvent.prototype.unbind;
MicroEvent.prototype.emit = MicroEvent.prototype.trigger;

// export in common js
if( typeof module !== "undefined" && ('exports' in module)){
        module.exports        = MicroEvent;
}

// AMD support
if( typeof define !== "undefined"){
                define([], function(){
                                return MicroEvent;
                });
}