JS实现图片新闻切换效果

2012-11-08 来源：网络
【实例名称】
JS实现图片新闻切换效果
【实例描述】
新闻切换技术想必大家都很熟悉，本例研究其切换效果如何实现。
【实例代码】
<html>
<head>
<style type="text/css">
body { text-align: center; margin:0; padding:0; 
background: #FFF; font-size:12px; color:#000;}
div,form,img,ul,ol,li,dl,dt,dd 
{margin: 0; padding: 0; border: 0;}
h1,h2,h3,h4,h5,h6 { margin:0; padding:0;}
table,td,tr,th{font-size:12px;}
a:link {color: #000; text-decoration:none;}
a:visited {color: #83006f;text-decoration:none;}
a:hover {color: #c00; text-decoration:underline;}
a:active {color: #000;}
.focusPic{margin:0 auto; width:244px;}
.focusPic .pic{margin:0 auto; width:240px; 
height:180px; padding:2px 0 0;}
.focusPic .adPic{margin:0 auto 5px; width:240px; height:29px; 
overflow:hidden;background:url(http://tech.163.com/newimg/adpic.gif);}
.focusPic .adPic .text{float:right; padding:9px 4px 0 0; width:140px;}
.focusPic .adPic .text a{color:#1f3a87;}
.focusPic .adPic .text a:hover{color:#bc2931;}
.focusPic h2{ float:left; width:232px;padding:4px 0 3px 12px; 
font-size:14px; text-align:left;}
.focusPic p{float:left; width:226px;line-height:160%; 
margin:0; text-align:left;padding:0 0 10px 12px;}
.focusPic p img {margin:0px 0 2px;}
.focusPic .more{ margin:0 auto; width:240px; }
.focusPic .more .textNum{float:right; 
margin:0 8px 0 0;padding:0 0 4px;}
.focusPic .more .textNum .text{float:left; 
font-weight:bold; padding:7px 6px 0 0; color:#666;}
.focusPic .more .textNum .num{float:left; width:113px; height:19px;}
.focusPic .more .textNum .bg1{ background:url(http://tech.163.com/newimg/num1.gif);}
.focusPic .more .textNum .bg2{ background:url(http://tech.163.com//num2.gif);}
.focusPic .more .textNum .bg3{ background:url(http://tech.163.com/newimg/num3.gif);}
.focusPic .more .textNum .bg4{ background:url(http://tech.163.com/newimg/num4.gif);}
.focusPic .more .textNum .num ul{ float:left; width:113px;}
.focusPic .more .textNum .num li{float:left; width:28px; 
font-weight:bold;display:block; color:#fff; list-style-type:none; padding:6px 0 0;}
.focusPic .more .textNum .num li a{color:#fff; padding:0 5px; }
.focusPic .more .textNum .num li a:visited{color:#fff;}
.focusPic .more .textNum .num li a:hover{color:#ff0;}
</style>
 <script language="JavaScript" type="text/javascript">
var nn;
nn=1;
setTimeout('change_img()',6000);
function change_img()
{
 if(nn>4) nn=1
 setTimeout('setFocus1('+nn+')',6000);
 nn++;
 tt=setTimeout('change_img()',6000);
}
function setFocus1(i)
{
 selectLayer1(i);
}
function selectLayer1(i)
{
 switch(i)
 {
 case 1:
 document.getElementById("focusPic1").style.display="block";
 document.getElementById("focusPic2").style.display="none";
 document.getElementById("focusPic3").style.display="none";
 document.getElementById("focusPic4").style.display="none";
 document.getElementById("focusPic1nav").style.display="block";
 document.getElementById("focusPic2nav").style.display="none";
 document.getElementById("focusPic3nav").style.display="none";
 document.getElementById("focusPic4nav").style.display="none";
 break;
 case 2:
 document.getElementById("focusPic1").style.display="none";
 document.getElementById("focusPic2").style.display="block";
 document.getElementById("focusPic3").style.display="none";
 document.getElementById("focusPic4").style.display="none";
 document.getElementById("focusPic1nav").style.display="none";
 document.getElementById("focusPic2nav").style.display="block";
 document.getElementById("focusPic3nav").style.display="none";
 document.getElementById("focusPic4nav").style.display="none";
 break;
 case 3:
 document.getElementById("focusPic1").style.display="none";
 document.getElementById("focusPic2").style.display="none";
 document.getElementById("focusPic3").style.display="block";
 document.getElementById("focusPic4").style.display="none";
 document.getElementById("focusPic1nav").style.display="none";
 document.getElementById("focusPic2nav").style.display="none";
 document.getElementById("focusPic3nav").style.display="block";
 document.getElementById("focusPic4nav").style.display="none";
 break;
 case 4:
 document.getElementById("focusPic1").style.display="none";
 document.getElementById("focusPic2").style.display="none";
 document.getElementById("focusPic3").style.display="none";
 document.getElementById("focusPic4").style.display="block";
 document.getElementById("focusPic1nav").style.display="none";
 document.getElementById("focusPic2nav").style.display="none";
 document.getElementById("focusPic3nav").style.display="none";
 document.getElementById("focusPic4nav").style.display="block";
 break;
 }
}
</script>
</head>
<body>
 <div class="focusPic">
 <div id="focusPic1" style="display:block ;">
 <div class="pic"> <a href="http://tech.163.com/11/0411/05/71BB3NO0000915BF.html">
<img src=http://img3.cache.netease.com/tech/2011/4/11/2011041105573667bd5.jpg 
alt="Facebook或年内曲线入华" width="240" height="180" border="0" /></a> </div>
 <h2><a href="http://tech.163.com/11/0411/05/71BB3NO0000915BF.html">
Facebook或年内曲线入华</a></h2>
 <p>有分析称，Facebook入华不外乎两条途径：一是成立合资公司，二是合作、收购。点击进入查看……
<img src="/newimg/i2.gif" alt="详细" width="3" height="5" /> 
<a href=http://tech.163.com/11/0411/05/71BB3NO0000915BF.html 
class="cDRed">详细</a></p>
 </div>
 <div id="focusPic2" style="display: none ;">
 <div class="pic"> <a href="http://tech.163.com/discover/">
<img src=http://cimg.163.com/tech/2006/1/17/200601171557008cee7.jpg 
alt="颠覆丛林动物生存法则" width="240" height="180" border="0" /></a> </div>
 <h2><a href="http://tech.163.com/discover/">颠覆丛林动物生存法则</a></h2>
 <p>群居动物的这种行为颠覆了我们通常认为的，在动物世界通行的 “丛林法则”，
动物不都自私，不都是弱肉强食的。<img src="/newimg/i2.gif" alt="详细" 
width="3" height="5" /> <a href="http://tech.163.com/discover/" class="cDRed">
详细</a></p>
 </div>
 <div id="focusPic3" style="display: none ;">
 <div class="pic"> <a href="http://tech.163.com/special/00091MNJ/itobserve015.html">
<img src="http://cimg.163.com/tech/2006/1/17/2006011711483290a60.jpg" alt="WAPI并非贸易阴谋" 
width="240" height="180" border="0" /></a> </div>
 <h2><a href="http://tech.163.com/special/00091MNJ/itobserve015.html">WAPI并非贸易阴谋</a>
</h2>
 <p>近日国家做出决定：“将向其他的国内及国外企业公布该算法”。事实证明中国WAPI标准并非是贸易阴谋。
<img src="/newimg/i2.gif" alt="详细" width="3" height="5" /> 
<a href="http://tech.163.com/special/00091MNJ/itobserve015.html" class="cDRed">
详细</a></p>
 </div>
 <div id="focusPic4" style="display: none ;">
 <div class="pic"> <a href="http://tech.163.com/special/00091OSI/horizons.html">
<img src=http://cimg.163.com/tech/2006/1/17/200601171002503f251.jpg 
alt="新视野号探测冥王星特别专题" width="240" height="180" border="0" /></a> </div>
 <h2><a href="http://tech.163.com/special/00091OSI/horizons.html">
新视野号探测冥王星特别专题</a></h2>
 <p>美国宇航局将于北京时间18日凌晨2时24分发射新视野号探测器，
造访这颗人类唯一尚未探测过的行星-冥王星。<img src="/newimg/i2.gif" alt="详细"
 width="3" height="5" /> <a href=http://tech.163.com/special/00091OSI/horizons.html 
class="cDRed">详细</a></p>
 </div>
 <div class="more">
 <div class="textNum">
 <div class="text">&gt; 更多头图新闻</div>
 <div class="num bg1" id="focusPic1nav" style="display: block;">
 <ul>
 <li>1</li>
 <li><a href="javascript:setFocus1(2);" target="_self">2</a></li>
 <li><a href="javascript:setFocus1(3);" target="_self">3</a></li>
 <li><a href="javascript:setFocus1(4);" target="_self">4</a></li>
 </ul>
 </div>
 <div class="num bg2" id="focusPic2nav" style="display: none;">
 <ul>
 <li><a href="javascript:setFocus1(1);" target="_self">1</a></li>
 <li>2</li>
 <li><a href="javascript:setFocus1(3);" target="_self">3</a></li>
 <li><a href="javascript:setFocus1(4);" target="_self">4</a></li>
 </ul>
 </div>
 <div class="num bg3" id="focusPic3nav" style="display: none;">
 <ul>
 <li><a href="javascript:setFocus1(1);" target="_self">1</a></li>
 <li><a href="javascript:setFocus1(2);" target="_self">2</a></li>
 <li>3</li>
 <li><a href="javascript:setFocus1(4);" target="_self">4</a></li>
 </ul>
 </div>
 <div class="num bg4" id="focusPic4nav" style="display: none;">
 <ul>
 <li><a href="javascript:setFocus1(1);" target="_self">1</a></li>
 <li><a href="javascript:setFocus1(2);" target="_self">2</a></li>
 <li><a href="javascript:setFocus1(3);" target="_self">3</a></li>
 <li>4</li>
 </ul>
 </div>
 </div>
 </div>
 </div>
</body>
</html>
需要在bodyr中添加一些新闻，注意这些新闻的布局。
【运行效果】
图片新闻切换效果运行效果