var services={
	title:"Services",
	dropdown:["Buy","Sell","GTFO"]
};
var contacts={
	title:"Contacts",
	dropdown:["1","2","3","4"]

};
var aboutUs={
	title:"About us",
	dropdown:["3","4"]
};
var menu=[services, contacts, aboutUs];

var ul = document.createElement("ul");
document.body.appendChild(ul);

for(i in menu){
	var li = document.createElement("li");
	ul.appendChild(li);
  	li.innerHTML=menu[i].title;

  	if(menu[i].dropdown != null && menu[i].dropdown.length!=0){
		var ul2 = document.createElement("ul");
		li.appendChild(ul2);
        ul2.style.display="none";
		(function (submenu) {
			li.onmouseover=function(){
			submenu.style.display="block";
			};
		})(ul2);

		for(j in menu[i].dropdown){
			var li2 = document.createElement("li");
			ul2.appendChild(li2);
			li2.innerHTML = menu[i].dropdown[j];
  		};
	}
}