function menu(){
		var m = document.getElementById('menu-principal');
		var lis = document.getElementsByTagName('li');
		for(var li in lis)
		{
			if(lis[li].parentNode && lis[li].parentNode.className == 'menu')
			{
				lis[li].onmouseover = function(){
					var uls = this.getElementsByTagName('ul');
					for(var ul in uls)
					{
						if(uls[ul].className == 'submenu')	
						{
							uls[ul].onmouseout = function(){
								this.style.display = 'none';
							}
							uls[ul].onmouseover = function(){
								this.style.display = 'block';
							}
							uls[ul].style.display = 'block';
						}
					}
				}
				lis[li].onmouseout = function(){
					var uls = this.getElementsByTagName('ul');
					for(var ul in uls)
					{
						if(uls[ul].className == 'submenu')	
						{
							uls[ul].style.display = 'none';
						}
					}
				}
			}
		}
	}