code: function(elem) {
          this.getOffset._offset = $(elem).offset();
  
          if (Garnish.$scrollContainer[0] !== Garnish.$win[0]) {
              this.getOffset._offset.top += Garnish.$scrollContainer.scrollTop();
              this.getOffset._offset.left += Garnish.$scrollContainer.scrollLeft();
          }
  
          return this.getOffset._offset;
      }
docs: Returns the offset of an element within the scroll container, whether that's the window or something else