PHP 大家帮我讲解一下这个文件 i.js 函数嵌套问题

/*
+---------------------------------------------------------------------------+
| ZYIIS.COM                                                                 |
| ==========                                                                |
|                                                                           |
| Copyright (c) 2005-2008 Zyiis Limited                                     |
| For contact details, see: http://www.zyiis.com/                           |
|                                                                           |
+---------------------------------------------------------------------------+
*/
(function(){
function s(b){
return b!=null?'"'+b+'"':'""'
}
function e(b){
if(typeof encodeURIComponent=="function"){
return encodeURIComponent(b)
}else{
return encodeURI(b)
}
}
function G(n,v){
if(v){
window.u_a_url+="&"+n+"="+v
}
}
function D(w,t,d){

var s=w.screen,j='0';tz=-t.getTimezoneOffset();
if(navigator.javaEnabled()) j='1';
if(s){
G("z_sh",s.height);
G("z_sw",s.width);
G("z_scd",s.colorDepth);
}
G("z_c_url",w.union_code_url);
G("z_uref",w.union_ref_url);
G("z_urefk",w.union_ref_k);
G("z_utz",tz/60);
G("z_uhis",history.length);
G("z_ujava",j);
G("z_ufv",F());
if(navigator.plugins){
G("z_unplug",navigator.plugins.length) 
}
if(navigator.mimeTypes){
G("z_unmime",navigator.mimeTypes.length)
}
}
function B(w,d){
return w.top.location==d.location
} function S(w,a,sr){
if(w.u_a_type=="1"){
a.write('<script language="JavaScript1.1" src='+s(sr)+" charset=gbk><\/script>")
}else{
a.write('<iframe name="u_a_iframe" width='+s(w.u_a_width)+" height="+s(w.u_a_height)+" frameborder=0 src="+s(sr)+' marginwidth="0" marginheight="0" vspace="0" hspace="0" allowtransparency="true" scrolling="no">');
a.write("</iframe>")
}
}
function A(){
var w=window,d=document,t=new Date;
w.u_a_url="http://localhost/show.php?";
w.u_a_url+="z_uid="+w.u_a_client;
w.u_a_url+="&zoneid="+w.u_a_zones;
if(w.union_num_ads_zone){
w.union_num_ads_zone=w.union_num_ads_zone+1
}
else{
w.union_num_ads_zone=1
}
if(w.union_num_ads_zone>10){
return
}
if(B(w,d)&&d.body){

var j=d.body.scrollHeight,v=d.body.clientHeight;
if(v&&j){
G("z_uc_ks",Math.round(j)) 
}
}
D(w,t,d);
S(w,d,w.u_a_url);
}

function C(w,d){
return true
}
function E(){
var w=window,d=document,e=null;g=d.referrer,w.onerror=C;
if(w.union_code_url==e){ 
w.union_code_url=escape(w.location); 
if(!B(w,d)){
w.union_code_url=g; 
}
}
w.union_ref_url = '';
if(B(w,d)&&g){
//w.union_ref_url=g;
w.union_ref_k=K(g);
}
}
var Z={};
function ya(b)
{
if(b in Z)return Z[b];
return Z[b]=navigator.userAgent.toLowerCase().indexOf(b)!=-1
}
function F(){
if(navigator.plugins&&navigator.mimeTypes.length)
{
var b=navigator.plugins["Shockwave Flash"];
if(b&&b.description)return b.description.replace(/([a-zA-Z]|\s)+/,
"").replace(/(\s)+r/,".")
}else if(navigator.userAgent&&navigator.userAgent.indexOf("Windows CE")>=0)
{
var a=3,c=1;
while(c)try
{
c=new ActiveXObject("ShockwaveFlash.ShockwaveFlash."+(a+1));
a++
}catch(e)
{
c=null
}return a.toString ()
}else if(ya("msie")&&!window.opera)
{
var c=null;
try
{
c=new ActiveXObject("ShockwaveFlash.ShockwaveFlash.7")
}catch(e)
{
var a=0;
try
{
c=new ActiveXObject("ShockwaveFlash.ShockwaveFlash.6");
a=6;
c.AllowScriptAccess="always"
}catch(e)
{
if(a==6)return a.toString ()
}try
{
c=new ActiveXObject("ShockwaveFlash.ShockwaveFlash")
}catch(e)
{

}
}if(c!=
null)
{
var a=c.GetVariable("$version").split(" ")[1];
return a.replace(/,/g,".")
}
}return "0"
}
function K(r){
var s=["wd","p","q","keyword","kw","w","key","word","query","q1","name"];
if(r!=""&&r!=null){
for(var i=0;i<s.length;i++){
var re=new RegExp("[^1-9a-zA-Z]"+s[i]+"=\([^&]*\)");
var kk=r.match(re);
if(kk!=null){
return kk[1];
}
}
}return "";
}
E();
A();
})();