XMLHttpRequest of ajax

        var wr = new java.io.OutputStreamWriter(conn.getOutputStream(), this._getCharset());
        wr.write(data);
        wr.flush();
        wr.close();
      }
      // read response headers
      // NOTE: the getHeaderField() methods always return nulls for me :(
      var gotContentEncoding = false;
      var gotContentLength = false;
      var gotContentType = false;
      var gotDate = false;
      var gotExpiration = false;
      var gotLastModified = false;
      for (var i = 0; ; i++)
      {
        var hdrName = conn.getHeaderFieldKey(i);
        var hdrValue = conn.getHeaderField(i);
        if (hdrName == null && hdrValue == null)
        {
          break;
        }
        if (hdrName != null)
        {
          this._headers[this._headers.length] = {h:hdrName, v:hdrValue};
          switch (hdrName.toLowerCase())
          {
            case 'content-encoding': gotContentEncoding = true; break;
            case 'content-length' : gotContentLength = true; break;
            case 'content-type' : gotContentType = true; break;
            case 'date' : gotDate = true; break;
            case 'expires' : gotExpiration = true; break;
            case 'last-modified' : gotLastModified = true; break;
          }
        }
      }
      // try to fill in any missing header information
      var val;
      val = conn.getContentEncoding();
      if (val != null && !gotContentEncoding) this._headers[this._headers.length] = {h:'Content-encoding', v:val};