基于jQuery插件jqzoom实现的图片放大镜效果示例

<script src="/js/common/jquery-1.6.2.js" type="text/javascript"></script>
<script src="/js/common/jquery.jqzoom.js" type="text/javascript"></script>

/*jQzoom*/
.jqzoom{
  border:1px solid #BBB;
  float:left;
  position:relative;
  padding:0px;
  cursor:pointer;
}
div.zoomdiv {
  z-index:  999;
  position        : absolute;
  top:0px;
  left:0px;
  width          : 200px;
  height         : 200px;
  background: #ffffff;
  border:1px solid #CCCCCC;
  display:none;
  text-align: center;
  overflow: hidden;
}
div.jqZoomPup {
  z-index         : 999;
  visibility       : hidden;
  position        : absolute;
  top:0px;
  left:0px;
  width          : 50px;
  height         : 50px;
  border: 1px solid #aaa;
  background: #ffffff url(/images/shopping/zoomlens.gif) 50% top no-repeat;
  opacity: 0.5;
  -moz-opacity: 0.5;
  -khtml-opacity: 0.5;
  filter: alpha(Opacity=50);
}

<div class="jqzoom">
  <img src="/images/shopping/pro_img/blue_one_small.jpg" style="width:300px; height:300px;" alt="" jqimg="/images/shopping/pro_img/blue_one_big.jpg" id="bigImg"/>
</div>

/*使用jqzoom*/
$(function() {
  $(".jqzoom").jqueryzoom({
    xzoom: 300, //放大图的宽度(默认是 200)
    yzoom: 300, //放大图的高度(默认是 200)
    offset: 10, //离原图的距离(默认是 10)
    position: "right", //放大图的定位(默认是 "right")
    preload: 1
  });
});

//**************************************************************
// jQZoom allows you to realize a small magnifier window,close
// to the image or images on your web page easily.
//
// jqZoom version 2.2
// Author Doc. Ing. Renzi Marco(www.mind-projects.it)
// First Release on Dec 05 2007
// i'm looking for a job,pick me up!!!
// mail: renzi.mrc@gmail.com
//**************************************************************
(function($){
    $.fn.jqueryzoom = function(options){
    var settings = {
        xzoom: 200,   //zoomed width default width
        yzoom: 200,   //zoomed div default width
        offset: 10,   //zoomed div default offset
        position: "right" ,//zoomed div default position,offset position is to the right of the image
        lens:1, //zooming lens over the image,by default is 1;
        preload: 1
      };
      if(options) {
        $.extend(settings, options);
      }
      var noalt='';
      $(this).hover(function(){
      var imageLeft = $(this).offset().left;
      var imageTop = $(this).offset().top;
      var imageWidth = $(this).children('img').get(0).offsetWidth;
      var imageHeight = $(this).children('img').get(0).offsetHeight;
      noalt= $(this).children("img").attr("alt");
      var bigimage = $(this).children("img").attr("jqimg");
      $(this).children("img").attr("alt",'');
      if($("div.zoomdiv").get().length == 0){
      $(this).after("<div class='zoomdiv'><img class='bigimg' src='"+bigimage+"'/></div>");
      $(this).append("<div class='jqZoomPup'> </div>");
      }
      if(settings.position == "right"){
      if(imageLeft + imageWidth + settings.offset + settings.xzoom > screen.width){
      leftpos = imageLeft - settings.offset - settings.xzoom;
      }else{
      leftpos = imageLeft + imageWidth + settings.offset;
      }
      }else{
      leftpos = imageLeft - settings.xzoom - settings.offset;
      if(leftpos < 0){
      leftpos = imageLeft + imageWidth + settings.offset;
      }
      }
      $("div.zoomdiv").css({ top: imageTop,left: leftpos });
      $("div.zoomdiv").width(settings.xzoom);
      $("div.zoomdiv").height(settings.yzoom);
      $("div.zoomdiv").show();
      if(!settings.lens){
       $(this).css('cursor','crosshair');
      }
          $(document.body).mousemove(function(e){
          mouse = new MouseEvent(e);
          /*$("div.jqZoomPup").hide();*/
          var bigwidth = $(".bigimg").get(0).offsetWidth;
          var bigheight = $(".bigimg").get(0).offsetHeight;
          var scaley ='x';
          var scalex= 'y';
          if(isNaN(scalex)|isNaN(scaley)){
          var scalex = (bigwidth/imageWidth);
          var scaley = (bigheight/imageHeight);
          $("div.jqZoomPup").width((settings.xzoom)/scalex );
          $("div.jqZoomPup").height((settings.yzoom)/scaley);
          if(settings.lens){
          $("div.jqZoomPup").css('visibility','visible');
          }
          }
          xpos = mouse.x - $("div.jqZoomPup").width()/2 - imageLeft;
          ypos = mouse.y - $("div.jqZoomPup").height()/2 - imageTop ;
          if(settings.lens){
          xpos = (mouse.x - $("div.jqZoomPup").width()/2 < imageLeft ) ? 0 : (mouse.x + $("div.jqZoomPup").width()/2 > imageWidth + imageLeft ) ? (imageWidth -$("div.jqZoomPup").width() -2) : xpos;
          ypos = (mouse.y - $("div.jqZoomPup").height()/2 < imageTop ) ? 0 : (mouse.y + $("div.jqZoomPup").height()/2 > imageHeight + imageTop ) ? (imageHeight - $("div.jqZoomPup").height() -2 ) : ypos;
          }
          if(settings.lens){
          $("div.jqZoomPup").css({ top: ypos,left: xpos });
          }
          scrolly = ypos;
          $("div.zoomdiv").get(0).scrollTop = scrolly * scaley;
          scrollx = xpos;
          $("div.zoomdiv").get(0).scrollLeft = (scrollx) * scalex ;
          });
      },function(){
        $(this).children("img").attr("alt",noalt);
        $(document.body).unbind("mousemove");
        if(settings.lens){
        $("div.jqZoomPup").remove();
        }
        $("div.zoomdiv").remove();
      });
    count = 0;
    if(settings.preload){
    $('body').append("<div style='display:none;' class='jqPreload"+count+"'>sdsdssdsd</div>");
    $(this).each(function(){
    var imagetopreload= $(this).children("img").attr("jqimg");
    var content = jQuery('div.jqPreload'+count+'').html();
    jQuery('div.jqPreload'+count+'').html(content+'<img src="'+imagetopreload+'">');
    });
    }
    }
})(jQuery);
function MouseEvent(e) {
   this.x = e.pageX;
   this.y = e.pageY;
}