IE 上下滚动展示模仿Marquee机制

var STARTINGOPACITY = 40;    //设置不透明度
var STARTINP = 70;//设置透明度
var SCROLLSTUP = 1;//滚动速度，1为一个像素
var SCROLLSYY = 100;//滚动时间请求
var reqflg = false;

// handles manual scrolling of the content //
function scrollContent(pardiv,id,sub) {
var div = document.getElementById("textslider");
var divsub = document.getElementById(sub);
var divpar = document.getElementById(pardiv);

clearInterval(div.timer);
div.style.opacity = STARTINGOPACITY * .01;
div.style.filter = 'alpha(opacity=' + STARTINP + ')';
var div2 = document.getElementById("textslider2");
if(div2!=null){
    clearInterval(div2.timer);
div2.style.opacity = STARTINGOPACITY * .01;
div2.style.filter = 'alpha(opacity=' + STARTINP + ')';
}

var tem = div.innerHTML;//第一个页
tem1 = "<div class=\"slidercontent1\" id=\"textslider2\">"+tem+"</div>";//第二个页

var objheight = divpar.offsetHeight;
var divheight = div.offsetHeight;

//判断是否需要滚屏，如果不需要就不滚动
if(objheight<divheight){
    if(!reqflg){
        divpar.innerHTML += tem1;
        reqflg = true;
        div = document.getElementById("textslider");
        div2 = document.getElementById("textslider2");
        //设置高度
        div2.style.top = divheight-1+ "px";
    }
    div.timer = setTimeout( function() { scrollAnimate(div,div2) }, SCROLLSYY);
}
}
function scrollAnimate(div,div2) {
//获取两个子div的top值
var divtop = div.offsetTop;
//alert(divtop);
if(divtop==0){
    div.style.top = "0px";
divtop = 0;
}
var div2top = div2.offsetTop;
if(div2top==0){
    div2top = 0;
div2.style.top = "0px";
}
if(divtop<div2top){
    //1号在上面 2号在下面
div.style.top = divtop - SCROLLSTUP+'px';
    div2.style.top = div2top - SCROLLSTUP+'px';
    //alert("div.style.top:"+div.style.top+"---div2.style.top:"+div2.style.top+":height:"+div.offsetHeight);
    //判断是否交换位置,如果高度位置等于top那么交换
    if(div.offsetTop==-div.offsetHeight){
     //将top设置为最下面
div.style.top = div2.offsetHeight;
    }
}else{
    //2号在上面 1号在下面
    div2.style.top = div2top - SCROLLSTUP+'px';
    div.style.top = divtop - SCROLLSTUP+'px';
    //判断是否交换位置,如果高度位置等于top那么交换
    if(div2.offsetTop==-div2.offsetHeight){
     //将top设置为最下面
div2.style.top = div.offsetHeight;
    }
}
div.timer = setTimeout( function() { scrollAnimate(div,div2) }, SCROLLSYY);
}

// cancel the scrolling on mouseout //
function cancelScroll(pardiv,id,sub) {
var div = document.getElementById(id);
div.style.opacity = 1;
div.style.filter = 'alpha(opacity=100)';
clearTimeout(div.timer);

var div2 = document.getElementById("textslider2");
if(div2!=null){
     div2.style.opacity = 1;
     div2.style.filter = 'alpha(opacity=100)';
     clearTimeout(div2.timer);
}
}