Cannot read property 'css' of undefined at Image.newImg.onload (jquery.elevatezoom.js:1188)

[sahilrihadh]

self.options.onImageSwap(self.$elem);

			newImg.onload = function() {
				self.largeWidth = newImg.width;
				self.largeHeight = newImg.height;
				self.zoomImage = largeimage;
				self.zoomWindow.css({ "background-size": self.largeWidth + 'px' + self.largeHeight + 'px' });
				self.swapAction(smallimage, largeimage);
				return;              
			}