Hi all,
I have taken from net drop down menu script
my web page is medistyle.az. It works perfectly
but when i look up code i cannot understand one thing there
below is code (js. file)

PHP Code:
var menu=function(){
    var 
t=15,z=50,s=6,a;
    function 
dd(n){this.n=nthis.h=[]; this.c=[]}
    
dd.prototype.init=function(p,c){
        
a=c; var w=document.getElementById(p), s=w.getElementsByTagName('ul'), l=s.lengthi=0;
        for(
i;i<l;i++){
            var 
h=s[i].parentNodethis.h[i]=hthis.c[i]=s[i];
            
h.onmouseover=new Function(this.n+'.st('+i+',true)');
            
h.onmouseout=new Function(this.n+'.st('+i+')');
        }
    }
    
dd.prototype.st=function(x,f){
        var 
c=this.c[x], h=this.h[x], p=h.getElementsByTagName('a')[0];
        
clearInterval(c.t); c.style.overflow='hidden';
        if(
f){
            
p.className+=' '+a;
            if(!
c.mh){c.style.display='block'c.style.height=''c.mh=c.offsetHeightc.style.height=0}
            if(
c.mh==c.offsetHeight){c.style.overflow='visible'}
            else{
c.style.zIndex=zz++; c.t=setInterval(function(){sl(c,1)},t)}
        }else{
p.className=p.className.replace(a,''); c.t=setInterval(function(){sl(c,-1)},t)}
    }
    function 
sl(c,f){
        var 
h=c.offsetHeight;
        if((
h<=0&&f!=1)||(h>=c.mh&&f==1)){
            if(
f==1){c.style.filter=''c.style.opacity=1c.style.overflow='visible'}
            
clearInterval(c.t); return
        }
        var 
d=(f==1)?Math.ceil((c.mh-h)/s):Math.ceil(h/s), o=h/c.mh;
        
c.style.opacity=oc.style.filter='alpha(opacity='+(o*100)+')';
        
c.style.height=h+(d*f)+'px'
    
}
    return{
dd:dd}
}(); 
Here i dont understand what does return{dd:dd} mean. I understand dd is name of function(class) but i couldnt understand what does syntax mean (return{dd:dd})
Thanks in advance for attention !!!