这种js现在用的很多。同时网上的js代码页很多。我直接从网上当了一个来用；代码如下：
html
<div
class="bannerbox">
<div
id="focus">
<ul>
<li><a href="#"
target="_blank">
<img src="../images/index_18.gif"
/></a></li>
<li><a href="#"
target="_blank">
<img src="../images/index_18.gif"
/></a></li>
<li><a href="#"
target="_blank">
<img src="../images/index_18.gif"
/></a></li>
<li><a href="#"
target="_blank">
<img src="../images/index_18.gif"
/></a></li>
</ul>
</div>
</div>
css：
.bannerbox { width: 970px; height: 447px; overflow: hidden; margin: 0px auto;
}
#focus { border:none;width: 970px; height: 447px; clear: both; overflow:
hidden; position: relative; float: left;z-index: 10 }
#focus ul { width:
970px; height: 447px; float: left; position: absolute; clear: both; padding:
0px; margin: 0px; border: none}
#focus ul li { float: left; width: 970px;
height: 447px; overflow: hidden; position: relative; padding: 0px;
margin:0;border: none }
#focus .preNext { width: 550px; height: 440px;
position: absolute; top: 2px; cursor: pointer;border: none;}
#focus .pre {
left: 0; background: url(../images/sprite.png) no-repeat left center;z-index:
20;border: none; }
#focus .next { right: 0; background:
url(../images/sprite1.png) no-repeat right center;z-index: 20;border: none;
}
jquery：
$(function () {
var sWidth =
$("#focus").width();
var len = $("#focus ul
li").length;
var index = 0;
var
picTimer;
var btn = "<div
class=‘btnBg‘></div><div class=‘btn‘>";
for
(var i = 0; i < len; i++) {
btn
+= "<span></span>";
}
btn += "</div><div class=‘preNext pre‘></div><div
class=‘preNext next‘></div>";
$("#focus").append(btn);
$("#focus .btnBg").css("opacity",
0);
$("#focus .btn span").css("opacity",
0.4).mouseenter(function () {
index = $("#focus .btn
span").index(this);
showPics(index);
}).eq(0).trigger("mouseenter");
$("#focus
.preNext").css("opacity", 0.0).hover(function ()
{
$(this).stop(true,
false).animate({ "opacity": "0.5" }, 300);
}, function ()
{
$(this).stop(true,
false).animate({ "opacity": "0" }, 300);
});
$("#focus .pre").click(function ()
{
index -=
1;
if (index == -1) { index = len
- 1; }
showPics(index);
});
$("#focus
.next").click(function () {
index
+= 1;
if (index == len) { index =
0; }
showPics(index);
});
$("#focus
ul").css("width", sWidth * (len));
$("#focus").hover(function () {
clearInterval(picTimer);
}, function ()
{
picTimer = setInterval(function
() {
showPics(index);
index++;
if (index == len) { index = 0; }
}, 2800);
}).trigger("mouseleave");
function showPics(index) {
var
nowLeft = -index * sWidth;
$("#focus ul").stop(true, false).animate({ "left": nowLeft },
300);
$("#focus .btn
span").stop(true, false).animate({ "opacity": "0.4" }, 300).eq(index).stop(true,
false).animate({ "opacity": "1" }, 300);
}
});
以上代码经测试在ie9以上，ff，chroom下运行正常。代码参考懒人图库
原文：http://www.cnblogs.com/lightinblack/p/3643843.html