code: function ( params, cache ) {
              var sp = ( this._path.indexOf('?') < 0 )? '?' : '&',
                  url = ( cache )? this._path : this._path + sp + 'requestTime=' + new Date().getTime();
      
              //URI encode
              if ( params ) {
                  var datas = params.split( '&' ),
                      paramNum = datas.length,
                      dataSet, i;
      
                  params = '';
                  for ( i = 0; i < paramNum; ++i ) {
                      dataSet = datas[i].split( '=' );
                      params += dataSet[0] + '=' + encodeURIComponent( dataSet[1] );
                      if ( i < paramNum - 1 ) params += '&';
                  }
              }
      
              this.xhr.onreadystatechange = this._handler;
      
              //GET
              if ( /get/i.test(this._method) ) {
                  if ( params && params != '' ) url += '&' + params;
                  this.xhr.open( 'GET', url, true );
                  this.xhr.send( null );
                  //POST
              } else {
                  this.xhr.open( 'POST', url, true );
                  this.xhr.setRequestHeader( 'Content-type', 'application/x-www-form-urlencoded; charset=' + this._charset );
                  this.xhr.send( params );
              }
              return this;
          }
docs: HttpRequest connect<br>
  다시 호출할려면 abort시킨후 호출해야한다.
  @param	{String}	params	예)count=100&time=100
  @param	{Boolean}	cache	GET으로 요청할때 캐시가 false면 url에 requestTime을 추가하여 캐시를 방지한다.