Mootools Fx.Index v1.0

At work I needed to perform an animation on a sprite-based image (e.g. one large image containing multiple stages within an animation, pre-rendered). Since there was no easy way within Mootools to iterate over an array of class names, I created one. I called it “Fx.Index”, but if you have a better name for it, please leave me a comment.

Fx.Index = Fx.Base.extend({
  initialize: function(el, css_classes, options) {
      this.element = $(el);
      this.css_classes = css_classes;
      this.parent(options);
      this.previous_index = null;
  },
  increase: function() {
      var index = this.now.toInt();
      if (this.previous_index == index)
          return;
      this.previous_index = index;
      var klass = this.css_classes[index];
      if ($chk(this.options.classBase))
          klass += " " + this.options.classBase;

      this.element.className = klass;
  }
});

This code is taken straight from our product, which uses Mootools 1.11. So I’ll post an update once I port it to Mootools 1.2, at which point I’ll submit it to be added in the not-yet-created plugin directory.