function scrollDoor(){
}
scrollDoor.prototype = {
sd : function(menus,divs,openClass,closeClass){
 var _this = this;
 if(menus.length != divs.length)
 {
  alert("菜单层数量和内容层数量不一样!");
  return false;
 }    
 for(var i = 0 ; i < menus.length ; i++)
 { 
  _this.$(menus[i]).value = i;    
  _this.$(menus[i]).onmouseover = function(){
     
   for(var j = 0 ; j < menus.length ; j++)
   {      
    _this.$(menus[j]).className = closeClass;
    _this.$(divs[j]).style.display = "none";
   }
   _this.$(menus[this.value]).className = openClass; 
   _this.$(divs[this.value]).style.display = "block";    
  }
 }
 },
$ : function(oid){
 if(typeof(oid) == "string")
 return document.getElementById(oid);
 return oid;
}
}