代码使用CSS3 css和圆角边框属性创建放大镜。Jquery是用来在光标位置坐标,并相应地改变背景的位置。轻轻移动光标的形象逐渐消失的放大镜将图像回到默认状态。
$(document).ready(function(){	var native_width = 0;	var native_height = 0;	//Now the mousemove function	$(".magnify").mousemove(function(e){		//When the user hovers on the image, the script will first calculate		//the native dimensions if they don't exist. Only after the native dimensions		//are available, the script will show the zoomed version.		if(!native_width && !native_height)		{			//This will  a new image object with the same image as that in .small			//We cannot directly get the dimensions from .small because of the 			//width specified to 200px in the html. To get the actual dimensions we have			//d this image object.			var image_object = new Image();			image_object.src = $(".small").attr("src");						//This code is wrapped in the .load function which is important.			//width and height of the object would return 0 if accessed before 			//the image gets loaded.			native_width = image_object.width;			native_height = image_object.height;		}		else		{			//x/y coordinates of the mouse			//This is the position of .magnify with respect to the document.			var magnify_offset = $(this).offset();			//We will deduct the positions of .magnify from the mouse positions with			//respect to the document to get the mouse positions with respect to the 			//container(.magnify)			var mx = e.pageX - magnify_offset.left;			var my = e.pageY - magnify_offset.top;						//Finally the code to fade out the glass if the mouse is outside the container			if(mx < $(this).width() && my < $(this).height() && mx > 0 && my > 0)			{				$(".large").fadeIn(100);			}			else			{				$(".large").fadeOut(100);			}			if($(".large").is(":visible"))			{				//The background position of .large will be changed according to the position				//of the mouse over the .small image. So we will get the ratio of the pixel				//under the mouse pointer with respect to the image and use that to position the 				//large image inside the magnifying glass				var rx = Math.round(mx/$(".small").width()*native_width - $(".large").width()/2)*-1;				var ry = Math.round(my/$(".small").height()*native_height - $(".large").height()/2)*-1;				var bgp = rx + "px " + ry + "px";								//Time to move the magnifying glass with the mouse				var px = mx - $(".large").width()/2;				var py = my - $(".large").height()/2;				//Now the glass moves with the mouse				//The logic is to deduct half of the glass's width and height from the 				//mouse coordinates to place it with its center at the mouse coordinates								//If you hover on the image now, you should see the magnifying glass in action				$(".large").css({left: px, top: py, backgroundPosition: bgp});			}		}	})})