event.js

Event: {
    arr: {},

    bind: function(eventNamesArr, cb) {
      !(eventNamesArr instanceof Array) && (eventNamesArr = [eventNamesArr]);
      for (var idx in eventNamesArr) {
        var eventName = eventNamesArr[idx];
        !(eventName in this.arr) && (this.arr[eventName] = []);
        this.arr[eventName].push(cb);
      }
    },

    unbind: function(eventName, cb) {
      if (!cb) {
        this.arr[eventName] = {};
      } else {
        for (var a = this.arr[eventName], i = a ? a.length - 1 : -1; i >= 0; --i) {
          if (a[i] === cb) {
            a.splice(i, 1);
            return;
          }
        }
      }
    },

    trigger: function(eventName, data) {
      if (eventName && eventName in this.arr) {
        for (var i = 0, a = this.arr[eventName], len = a.length; i < len; i++) {
          a[i](data);
        }
      }
    }
  }