js 文字滚动效果

Meng.extend({
zbjScrollText:function(scrollId){
var li = Meng.getTag('li',Meng.getId(scrollId)),

curActLi = 0,
getActivity = function(){
return [li[curActLi],li[10+curActLi],li[20+curActLi],li[30+curActLi]];
},
sliceDown = function(elem,pos){
Meng.setStyle(elem,{top:'-60px',zIndex:1});
Meng.animate(elem,{top:-60},{top:60},800);
},
play = function(){
Meng.each(getActivity(),function(i){
var _this = this;
setTimeout(function(){
sliceDown(_this,i);
},i*900);
});
};
play();
setInterval(function(){
if(curActLi == 9){
curActLi = 0;
Meng.each(li,function(){Meng.setStyle(this,{zIndex:0})});
}else curActLi++;
play();
},5000);
}
});
Meng.zbjScrollText('dota1');