title: Prototype's Effect.Parallel equivalent in jQuery
body: <p>I am trying to convert a Prototype slide-show plugin to jQuery. The animation function is fairly simple an intuitive: fade-out visible slide, fade-in next slide, both animations start and stop at the same time. Here is the Prototype code which I have yet to fully understand:</p>
  
  <pre><code>fadeInOut: function (a, b) {
      new Effect.Parallel(
          [
              new Effect.Fade(b, {sync: true}),
              new Effect.Appear(a, {sync: true})
          ], {
              duration: 1
          }
      );
  }
  </code></pre>
  
  <p>I've written this jQuery equivalent:</p>
  
  <pre><code>var anim = function (a, b) {
      // m_Locked = true
      a.fadeOut(1000);
      b.fadeIn(1000);
      // m_Locked = false
  };
  </code></pre>
  
  <p>I am wondering what does Effect.Parallel do and if there is a jQuery equivalent. I also need to set and clear a locked flag which i'll use to disable buttons while the animation is running... this does not seem to work.</p>