what's the meaning of the functions in javascript?
<pre><code>  function ExChgClsName(Obj,NameA,NameB){
 var Obj=document.getElementById(Obj)?document.getElementById(Obj):Obj;
 Obj.className=Obj.className==NameA?NameB:NameA;
}

&lt;a href="javascript:showMenu(2);"&gt;
</code></pre>

<p>i am a newbie of the js. so can't understand the above two function very well. expect someone can explain the line's meaning  to me one by one. many thanks.</p>
