Why this script load AssetBundle can not work in webplayer?

 using UnityEngine;
  using System.Collections;
  using System.IO;
  using System;
  using Object=UnityEngine.Object;
  
 public class LoadABs : MonoBehaviour 
 {
  public string path;
 
 
  // Use this for initialization
  IEnumerator Start () 
 {
  if(Application.platform == RuntimePlatform.WindowsWebPlayer)
  {
  path = Application.dataPath + "/ABs";
  }
  else
  {
  path = Application.dataPath + "/../ABs";
  }
 
  System.Random r = new System.Random();
 
  string[] files = Directory.GetFiles(path);
  if (files.Length != 0) 
 {
  foreach (string file in files)
  {
  Debug.Log(file);
  WWW www = new WWW("file://" + file);
  yield return www;
  if (www.isDone) 
 {
  Object obj = www.assetBundle.mainAsset;
  GameObject go = (GameObject)Instantiate(obj);
  go.transform.position = new Vector3(r.Next(10), 0, r.Next(10));
  Debug.Log(go.name);
  }
  }
  }
  }
  
 }
  

I use the script to test, it works good in editor and exe version, however I build to webplayer, it can not work. Why? Web need difference way? Any suggest is very grateful.