code: function(isLarge) {
  			var el;
  			if(isLarge) {
  				el = mfp.currItem.img;
  			} else {
  				el = mfp.st.zoom.opener(mfp.currItem.el || mfp.currItem);
  			}
  
  			var offset = el.offset();
  			var paddingTop = parseInt(el.css('padding-top'),10);
  			var paddingBottom = parseInt(el.css('padding-bottom'),10);
  			offset.top -= ( $(window).scrollTop() - paddingTop );
  
  
  			/*
  			
  			Animating left + top + width/height looks glitchy in Firefox, but perfect in Chrome. And vice-versa.
  
  			 */
  			var obj = {
  				width: el.width(),
  				// fix Zepto height+padding issue
  				height: (_isJQ ? el.innerHeight() : el[0].offsetHeight) - paddingBottom - paddingTop
  			};
  
  			// I hate to do this, but there is no another option
  			if( getHasMozTransform() ) {
  				obj['-moz-transform'] = obj['transform'] = 'translate(' + offset.left + 'px,' + offset.top + 'px)';
  			} else {
  				obj.left = offset.left;
  				obj.top = offset.top;
  			}
  			return obj;
  		}
docs: Get element postion relative to viewport