鼠标放在图片上，跟随鼠标显示大图，图片提示

    <ul>
        <li><a href="images/apple_1_bigger.jpg" class="tooltip" title="苹果 iPod"><img src="images/apple_1.jpg" alt="苹果 iPod" /></a></li>
        <li><a href="images/apple_2_bigger.jpg" class="tooltip" title="苹果 iPod nano"><img src="images/apple_2.jpg" alt="苹果 iPod nano"/></a></li>
        <li><a href="images/apple_3_bigger.jpg" class="tooltip" title="苹果 iPhone"><img src="images/apple_3.jpg" alt="苹果 iPhone"/></a></li>
        <li><a href="images/apple_4_bigger.jpg" class="tooltip" title="苹果 Mac"><img src="images/apple_4.jpg" alt="苹果 Mac"/></a></li>
    </ul>

<script type="text/javascript">

$(function(){
    var x = 10;
    var y = 20;
    $("a.tooltip").mouseover(function(e){
        this.myTitle = this.title;
        this.title = "";    
        var imgTitle = this.myTitle? "<br/>" + this.myTitle : "";
        var tooltip = "<div id=‘tooltip‘><img src=‘"+ this.href +"‘ alt=‘产品预览图‘/>"+imgTitle+"<\/div>"; //创建 div 元素
        $("body").append(tooltip);    //把它追加到文档中                         
        $("#tooltip")
            .css({
                "top": (e.pageY+y) + "px",
                "left":  (e.pageX+x)  + "px"
            }).show("fast");      //设置x坐标和y坐标，并且显示
    }).mouseout(function(){
        this.title = this.myTitle;    
        $("#tooltip").remove();     //移除 
    }).mousemove(function(e){
        $("#tooltip")
            .css({
                "top": (e.pageY+y) + "px",
                "left":  (e.pageX+x)  + "px"
            });
    });
})

</script>