// JavaScript Document--picture switch

var curIndex=0;
 //时间间隔 单位毫秒
 var timeInterval=1500;
 var arr=new Array();
 arr[0]="http://www.innovateda.org/english/images/header-1.gif";
 arr[1]="http://www.innovateda.org/english/images/header-2.gif";

setInterval(changeImg,timeInterval);
function changeImg()
{
    var obj=document.getElementById("obj");
    if (curIndex==arr.length-1) 
    {
        curIndex=0;
    }
    else    {
        curIndex+=1;
    }
    obj.src=arr[curIndex];
}