code: function ( propStr ) {
              if ( window.getComputedStyle ) {
                  this.css = function ( propStr ) {
                      var el = this.element();
      
                      //setter
                      if ( propStr && propStr.indexOf(':') > -1 ) {
                          $B.style.inline( el, propStr );
                          //getter
                      } else {
                          return $B.style.current( el, propStr );
                      }
                  };
      
                  //IE6~8
              } else if ( document.documentElement.currentStyle ) {
                  this.css = function ( propStr ) {
                      var el = this.element();
      
                      //setter
                      if ( propStr && propStr.indexOf(':') > -1 ) {
                          //opacity
                          if ( propStr.indexOf('opacity') > -1 ) {
                              $B.style.opacity( el, $B.style.parse( propStr ).opacity.value );
                          } else {
                              $B.style.inline( el, propStr );
                          }
      
                          //getter
                      } else {
                          return ( propStr && propStr.indexOf('opacity') > -1 )? $B.style.opacity( el ) : $B.style.computed( el, propStr );
                      }
                  };
              }
      
              return this.css( propStr );
          }
docs: 타겟타입:(Selector, Element)
  Inline Style설정, ComputedStyle을 반환
  @param	{String}	propStr		"width:100px; z-index:2" 표기법, 입력하지 않으면 all (property를 입력하여 값을 구하는것이 정확하다)
  @return	{String}