基于jQuery仿淘宝产品图片放大镜特效

<div class="infoimg">
 <div class="mainImg" id="largePicDiv">
  <img id="largePic" src="FileUpload/20160120/20160120103334758_w.jpg" alt="" />
  <div class="zoom_pup" id="move"></div>
  <div id="detailPic" class="big_pic">
   <img alt="和朋友们一起想办法（第二辑）：全8册" src="FileUpload/20160120/20160120103334758_b.jpg" />
  </div>
 </div>
 <div class="allImg">
   <img src="FileUpload/20160120/20160120103334758_x.jpg" alt="和朋友们一起想办法（第二辑）：全8册"/>
   <img src="FileUpload/20160120/20160120103334918_x.jpg" alt="和朋友们一起想办法（第二辑）：全8册"/>
   <img src="FileUpload/20160120/20160120103335031_x.jpg" alt="和朋友们一起想办法（第二辑）：全8册"/>
   <img src="FileUpload/20160120/20160120103335127_x.jpg" alt="和朋友们一起想办法（第二辑）：全8册"/>
   <img src="FileUpload/20160120/20160120103335209_x.jpg" alt="和朋友们一起想办法（第二辑）：全8册"/>

 </div>
    
</div>

.infoimg { float: left; padding: 0 20px 30px 0; position: relative; width: 320px; }

.infoimg img { display: block; height: 320px; width: 320px; }

.allImg { height: 58px; margin: 15px 0 0 10px; overflow: hidden; width: 310px; }

.allImg img { cursor: pointer; float: left; height: 54px; margin-right: 3px; padding: 2px; width: 54px; }

.allImg img.current { border: 1px solid #f1f1f1; padding: 1px; }

.mainImg { position: relative; }

.mainImg .zoom_pup { background: url("../images/zoom_pup.png") repeat 0 0; cursor: move; height: 175px; left: 0px; position: absolute; top: 160px; width: 175px; display: none; }

.big_pic { background-color:#fff; border: 1px solid #f5f5f5; height: 400px; left: 320px; overflow: hidden; position: absolute; text-align: center; top: 0; width: 400px; display: none; }
.big_pic img{ width: 800px; height: 800px;}

//切换图片
 $(".allImg img").mouseover(function() {
  $(".allImg img").removeClass("current");
  $(this).addClass("current");
  var src = $(this).attr("src");
  $("#largePic").attr("src", src.replace("_x", "_w"));
  $("#detailPic img").attr("src", src.replace("_x", "_b"));

 });
 
 //放大镜效果
 $("#largePicDiv").bind("mousemove",
  function(e) {
   var ev = e || event;
   var mouseX = ev.pageX;
   var mouseY = ev.pageY;
   var picLeft = $("#largePic").offset().left;
   var picTop = $("#largePic").offset().top;
   var picWidth = $("#largePic").width();
   var picHeight = $("#largePic").height();
   var xLength = mouseX - picLeft;
   var yLength = mouseY - picTop;
   var qWidth = picWidth / 4;
   var lastQWidth = picWidth - picWidth / 4;
   var qHeight = picHeight / 4;
   var lastQHeight = picHeight - picHeight / 4;
   if (xLength < qWidth) {
    $("#move").css("left","0px");
   } else {
    if (xLength > lastQWidth) {
     $("#move").css("left", (lastQWidth - qWidth) + "px");
    } else {
     $("#move").css("left", (xLength - qWidth) + "px");
    }
   }
   if (yLength < qHeight) {
    $("#move").css("top", "0px");
   } else {
    if (yLength > lastQHeight) {
     $("#move").css("top", (lastQHeight - qHeight) + "px");
    } else {
     $("#move").css("top", (yLength - qHeight) + "px");
    }
   }
   $("#detailPic > img").css("left", parseInt($("#move").css("left")) * (-800 / picWidth) + "px").css("top", parseInt($("#move").css("top")) * (-800 / picWidth) + "px").css("position", "absolute");
  });