   size: 30, // particle size in pixels
    },
  };
  (
          function(){
            var b=0;
            var c=["ms","moz","webkit","o"];
            for(var a=0;a<c.length&&!window.requestAnimationFrame;++a){
              window.requestAnimationFrame=window[c[a]+"RequestAnimationFrame"];
              window.cancelAnimationFrame=window[c[a]+"CancelAnimationFrame"]||window[c[a]+"CancelRequestAnimationFrame"]
            }
            if(!window.requestAnimationFrame){
              window