js动态切换图片

<script language =javascript >
    $(function () {
        initAds();

    });
    function initAds() {
        var curIndex = 0;
        var timeInterval = 2500;
        var arr = new Array();
        arr[0] = "../../Resource/img/lizi/ad-img1.png";
        arr[1] = "../../Resource/img/lizi/ad-img2.png";
        arr[2] = "../../Resource/img/lizi/ad-img3.png";
        setInterval(changeImg, timeInterval);
        function changeImg() {
            var obj11 = document.getElementById("obj");
            if (curIndex == arr.length - 1) {
                curIndex = 0; 
            }
            else {
                curIndex += 1;
            }
            obj11.src = arr[curIndex];
        }
    }
   
</script>