急急急！！！那位仁兄能帮我解释一下这段js代码，小弟不甚感激

[fengzhengju]

急急急！！！那位仁兄能帮我解释一下这段js代码，小弟不甚感激。
<script type=text/javascript>
function getid(o)
{
return (typeof o == "object")? o : document.getElementById(o);
}

function getNames(obj,name,tij)
{
var plist = getid(obj).getElementsByTagName(tij);
var rlist = new Array();
for(i=0;i<plist.length;i++)
{
if(plist[i].getAttribute("name") == name)
{
rlist[rlist.length] = plist[i];
}
}
return rlist;
}

function fiterplay(obj,num,t,name,c1,c2)
{
var fitlist = getNames(obj,name,t);
for(i=0;i<fitlist.length;i++)
{
if(i == num)
fitlist[i].className = c1;
else
fitlist[i].className = c2;
}
}

function play(obj,num)
{
var s = getid('simg');
var i = getid('info');
var b = getid('bimg');
try
{
with(b)
{
filters[0].Apply();

fiterplay(b,num,"div","f","show","dis1");
fiterplay(s,num,"div","f","s","");
fiterplay(i,num,"div","f","show","dis1");
filters[0].play();
}
}
catch(e)
{
fiterplay(b,num,"div","f","show","dis1");
fiterplay(s,num,"div","f","s","");
fiterplay(i,num,"div","f","show","dis1");
}
}
function format()
{
var s = getid('simg');
var l = getNames(s,"f","div")
for(i=0;i<l.length;i++)
{
l[i].num = i;
l[i].onclick = function()
{
play(this,this.num);
}
}
}

var autoStart = 0;
var n = 0;
function clearAuto() {clearInterval(autoStart);};
function setAuto(){autoStart=setInterval("auto(n)", 6000)}
function auto()
{
var s = getid("simg");
var x = getNames(s,"f","div");
n++;
if(n>(x.length-1))
{ n = 0; }
play(x[n],n);
}
format();
setAuto();
</script>
帮我解释一下这段代码详细点（每句都解释就再好不过了），小弟感激涕零

[c_hua6280]

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