Javascript实现滚动图片新闻

/*
 * 下面这段代码是用来实现图片新闻的
 */
var index = 0;
var Timer = null;

function initGallery(){
    for(var i=0; i< 4; i++){
       document.getElementById("fPic"+i).style.display = "none";
       document.getElementById("fTitl"+i).style.display = "none";
       document.getElementById("fNum"+i).style.className = "numOff";
    }
    startChange();
    setTimer();
}

function startChange(){
    index = index % 4;

    changePic(index);
    changeTitl(index);
    changeNum(index);

    index++;
}

function changePic(index){
    for(var i=0; i<4;i++){
        document.getElementById("fPic"+i).style.display = "none";
    }
    document.getElementById("fPic"+index).style.display = "block";
}

function changeTitl(index){
    for(var i=0; i<4; i++){
        document.getElementById("fTitl"+i).style.display = "none";
    }
    document.getElementById("fTitl"+index).style.display = "block";
}

function changeNum(index){
    for(var i=0; i<4; i++){
        document.getElementById("fNum"+i).className = "numOff";
    }
    document.getElementById("fNum"+index).className = "numOff numOn";
}

function clearTimer(){
    this.clearInterval(Timer);
}

function setTimer(){
    Timer = window.setInterval(startChange, 3000)
}

function setIndex(index){
    this.index = index;
    this.startChange();
}