js 随机变换图片

       <div style="position:absolute;left:40%;top:10%;border-style:dotted">
           <img src="ejb.jpg"/><br/>
           <input type="button" value="随机选择人物"/>
           <input type="button" value="暂停"/>
       </div>
       <script type="text/javascript">
          //创建一个数组
          var paths = new Array();
           var isExecute = true;
           var count=0;
           window.onload = function(){
               //将N张图片的路径放入数组中
               paths[0]="ejb.jpg";
               paths[1]="j2ee.jpg";
               paths[2]="java.gif";
               paths[3]="javamail.gif";
           }
           //随机选择人物
           document.getElementsByTagName("input")[0].onclick=function(){
               window.setInterval("changeImage()",500);
               isExecute=true;
           }
           //换图片
           function changeImage(){
               if(isExecute){
                   //随机选取一张图片
                   var path = getPath();
                   //动态修改图片的src属性值
                   var imgElement = document.images[0];
                   imgElement.src = path;
               }
           }
           //随机选中一张图片的路径
           function getPath(){
               //随机获取0,1,2中的任何一个型值
               var index = Math.floor(Math.random()*4);
               count=count+1>3?0:count+1;
               return paths[count];
               //return paths[index];
           }
           //暂停
           document.getElementsByTagName("input")[1].onclick=function(){
               isExecute = false;
           }
       </script>