code: function ( parent, selector ) {
              var selectList = this.selectorList( selector ),
                  selNum = selectList.length,
                  finishObj = this.parse( selectList[0].selector ),
                  matchEl;
      
              //조건이 ID만 있을때
              if ( selNum == 1 && finishObj.length == 1 && finishObj.id ) {
                  return document.getElementById( finishObj.id.replace('#', '') );
                  //조건 검색
              } else {
                  //모든태그 검색
                  var allTag = parent.getElementsByTagName( finishObj.node || '*' ),
                      i, tagNum = allTag.length;
      
                  for ( i = 0; i < tagNum; ++i ) {
                      var tag = allTag[i];
                      //첫번째 조건 검사
                      if ( this.match( tag, finishObj ) ) {
                          if ( selNum > 1 ) {
                              if ( this.depthMatch( parent, tag, selectList, 0 ) ) {
                                  matchEl = tag;
                                  break;
                              }
                          } else {
                              matchEl = tag;
                              break;
                          }
                      }
                  }
              }
              return matchEl;
          }
docs: 단일검색, parent는 반드시 입력해야 한다. 없으면 document라도 입력.