jquery左右滚动焦点图banner图片鼠标经过显示上下页按钮

jquery左右滚动焦点图banner图片,鼠标经过显示上下页
适合宽和高都比较大的页面使用
 
演示

<div class="bannerbox"> 
<div id="focus"> 
<ul> 
<li><a href="http://www.freejs.net/" target="_blank"> 
<img src="../dandong.png" alt="" /></a></li> 
<li><a href="http://www.freejs.net/" target="_blank"> 
<img src="../mohe.png" alt="" /></a></li> 
<li><a href="http://www.freejs.net/" target="_blank"> 
<img src="../changbaishan.png" alt="" /></a></li> 
<li><a href="http://www.freejs.net/" target="_blank"> 
<img src="../erlianhaote.png" alt="" /></a></li> 
</ul> 
</div> 
</div>

@charset "utf-8"; 
img { border: 0px; } 
.bannerbox { width: 320px; height: 150px; overflow: hidden; margin: 0px auto; } 
#focus { width: 320px; height: 150px; clear: both; overflow: hidden; position: relative; float: left; } 
#focus ul { width: 320px; height: 150px; float: left; position: absolute; clear: both; padding: 0px; margin: 0px; } 
#focus ul li { float: left; width: 320px; height: 150px; overflow: hidden; position: relative; padding: 0px; margin: 0px; } 
#focus .preNext { width: 250px; height: 150px; position: absolute; top: 0px; cursor: pointer; } 
#focus .pre { left: 0; background: url(../images/sprite.png) no-repeat left center; } 
#focus .next { rightright: 0; background: url(../images/sprite1.png) no-repeat rightright center; }

js文件

$(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); 
} 
});