【求教】

下面是帖子滚动代码，是被人复制别人的
请问怎么修改此段代码的滚动速度
<style type="text/css">
ul,li{list-style:none;}
.wplck{position:relative;height:370px;overflow:hidden;margin:0px auto; }
.sliderlck{position:absolute;width:98%;}
.fllck{float:left;}
.sliderlck img{display:inline;padding:2px;border:0}
.sliderlck li{padding:5px 0;border-bottom:1px dashed #ccc;overflow:hidden;width:100%;}
.sliderlck p{font-size:12px;padding-left:46px;color:#666;line-height:18px;}
</style>
<script type="text/javascript">
function H$(i) {return document.getElementById(i)}
function H$(c, p) {return p.getElementsByTagName(c)}
var sliderlck = function () {
function init (o) {
this.id = o.id;
this.at = o.auto ? o.auto : 3;
this.o = 0;
this.pos();
}
init.prototype = {
pos : function () {
clearInterval(this.__b);
this.o = 0;
var el = H$(this.id), li = H$('li', el), l = li.length;
var _t = li[l-1].offsetHeight;
var cl = li[l-1].cloneNode(true);
cl.style.opacity = 0; cl.style.filter = 'alpha(opacity=0)';
el.insertBefore(cl, el.firstChild);
el.style.top = -_t + 'px';
this.anim();
},
anim : function () {
var _this = this;
this.__a = setInterval(function(){_this.animH()}, 20);
},
animH : function () {
var _t = parseInt(H$(this.id).style.top), _this = this;
if (_t >= -1) {
clearInterval(this.__a);
H$(this.id).style.top = 0;
var list = H$('li',H$(this.id));
H$(this.id).removeChild(list[list.length-1]);
this.__c = setInterval(function(){_this.animO()}, 20);
//this.auto();
}else {
var __t = Math.abs(_t) - Math.ceil(Math.abs(_t)*.07);
H$(this.id).style.top = -__t + 'px';
}
},
animO : function () {
this.o += 2;
if (this.o == 100) {
clearInterval(this.__c);
H$('li',H$(this.id))[0].style.opacity = 1;
H$('li',H$(this.id))[0].style.filter = 'alpha(opacity=100)';
this.auto();
}else {
H$('li',H$(this.id))[0].style.opacity = this.o/100;
H$('li',H$(this.id))[0].style.filter = 'alpha(opacity='+this.o+')';
}
},
auto : function () {
var _this = this;
this.__b = setInterval(function(){_this.pos()}, this.at*1000);
}
}
return init;
}();
</script>
</head>
<div class="wplck">
<ul id="sliderlck" class="sliderlck">
[loop]
<li>
<a class="fllck" href="home.php?mod=space&uid={authorid}" {target}><img src="{avatar}" width="33" height="33" alt="{author}" /></a>
<p><a href="{url}" title="{title}"{target}>{title}</a></p>
<p><em class="xg1 xw0">{summary}</em> <a style="color:#CCC" href="{url}"{target}>[详细]</a></p>
</li>
[/loop]
</ul>
</div>
<script type="text/javascript">
new sliderlck({id:'sliderlck'})
</script>