title: Different in "scope" and "context" in this Javascript code
body: <p>I'm using this basic event system in my Javascript code and I'm trying to document it for my coworkers.  I'm not really sure what the difference is in "scope" and "context" in this code.  Can anyone help me understand why I even need them both?</p>
  
  <pre><code>this.myClass.prototype.on = function (type, method, scope, context) {
      var listeners, handlers, scope;
      if ( !(listeners = this.listeners) ) {
          listeners = this.listeners = {};
      }
  
      if ( !(handlers = listeners[type]) ) {
          handlers = listeners[type] = [];
      }
  
      scope = (scope ? scope : window);
      handlers.push({
          method: method,
          scope: scope,
          context: (context ? context : scope)
      });
  }
  
  this.myClass.prototype.trigger = function(type, data, context) {
      var listeners, handlers, i, n, handler, scope;
      if (!(listeners = this.listeners)) {
          return;
      }
      if (!(handlers = listeners[type])){
          return;
      }
      for (i = 0, n = handlers.length; i &lt; n; i++){
          handler = handlers[i];
          if (context &amp;&amp; context !== handler.context) continue;
          if (handler.method.call(
              handler.scope, this, type, data
          )===false) {
              return false;
          }
      }
      return true;
  }
  </code></pre>