[рони]

Опан,

var myfiles=["1.mp3","2.mp3","3.mp3","4.mp3","5.mp3"];
 audio.onended=  function (){
  var len = myfiles.length;
  if(len){
     len *= Math.random();
     len |= 0;
     len = "audio/"+myfiles.splice(len,1)[0]
     this.src=len;
     this.play();
  }
};