点击缩小图片并显示注释信息的jQuery特效

    点击大图，就会缩小图片，并且显示半透明黑色背景的图片的注释信息，覆盖于缩小后图片之上。
1、在head引入下面的代码：

<link rel="stylesheet" href="css/style.css" type="text/css" media="screen"/>

2、在body引入下面的代码：

<div id="portfolio" class="portfolio">
    <div class="portfolio_item">
        <div class="image_wrap">
            <img src="images/website1.jpg" alt="Website1"/>
        </div>
        <div class="zoom_overlay">
            <img src="images/website1_notes.png" alt="Website1Notes"/>
        </div>
    </div>
    <div class="portfolio_item">
        <div class="image_wrap">
            <img src="images/website2.jpg" alt="Website2"/>
        </div>
        <div class="zoom_overlay">
            <img src="images/website2_notes.png" alt="Website2Notes"/>
        </div>
    </div>
    <div class="portfolio_item">
        <div class="image_wrap">
            <img src="images/website3.jpg" alt="Website3"/>
        </div>
        <div class="zoom_overlay">
            <img src="images/website3_notes.png" alt="Website3Notes"/>
        </div>
    </div>
    <div class="portfolio_item">
        <div class="image_wrap">
            <img src="images/website4.jpg" alt="Website4"/>
        </div>
        <div class="zoom_overlay">
            <img src="images/website4_notes.png" alt="Website4Notes"/>
        </div>
    </div>
    <div class="portfolio_item">
        <div class="image_wrap">
            <img src="images/website5.jpg" alt="Website5"/>
        </div>
        <div class="zoom_overlay">
            <img src="images/website5_notes.png" alt="Website5Notes"/>
        </div>    
    </div>
</div>

<!-- The JavaScript -->
<script type="text/javascript" src="http://www.5imoban.net/download/jquery/jquery-1.4.2.min.js"></script>
<script type="text/javascript">
    $(function() {
        //main div
        var $portfolio    = $('#portfolio');
        
        //click event for the image :
        //show the overlay
        $portfolio.find('.image_wrap').bind('click',function(){
            var $elem    = $(this);
            var $image    = $elem.find('img:first');
            $image.stop(true)
                  .animate({
                    'width'    :'400px',
                    'height':'400px'
                  },250);
                  
            //the overlay is the next element
            var opacity    = '1';
            if($.browser.msie)
                opacity    = '0.5'
            $elem.next()
                 .stop(true)
                 .animate({
                    'width'        :'500px',
                    'height'    :'500px',
                    'marginTop'    :'-250px',
                    'marginLeft':'-250px',
                    'opacity'    :opacity
                },250,function(){
                    //fade in the annotations
                    $(this).find('img').fadeIn();
                });
        });
        
        //click event for the overlay :
        //show the image again and hide the overlay
        $portfolio.find('.zoom_overlay').bind('click',function(){
            var $elem    = $(this);
            var $image    = $elem.prev()
                               .find('img:first');
            //hide overlay
            $elem.find('img')
                 .hide()
                 .end()
                 .stop(true)
                 .animate({
                    'width'        :'400px',
                    'height'    :'400px',
                    'marginTop'    :'-200px',
                    'marginLeft':'-200px',
                    'opacity'    :'0'
                 },125,function(){
                    //hide overlay
                    $(this).hide();
                 });
                
            //show image    
            $image.stop(true)
                  .animate({
                    'width':'500px',
                    'height':'500px'
                  },250);
        });
    });
</script>