function prepare_menu()
{
	var lis=document.getElementById('menu').getElementsByTagName('li');
	for(i=0;lis.length>i;i++)
	{
		lis[i].onmouseover=show_child_ul;
		lis[i].onmouseout=hide_all_child;
	}
	
	
}
function hide_all_child()
{
	var uls=document.getElementById('menu').getElementsByTagName('ul');
	for(i=0;uls.length>i;i++)
	{
		uls[i].style.display='none';
		uls[i].style.visibility='hidden';
	}
	var selects=document.getElementsByTagName('select');
	for(i=0;selects.length>i;i++) selects[i].style.visibility='visible';
	
}
function show_child_ul()
{
	hide_all_child();
	var selects=document.getElementsByTagName('select');
	for(i=0;selects.length>i;i++){ selects[i].style.visibility='hidden';}
	var child_menu=this.getElementsByTagName('ul');
	if(child_menu.length>0)
	{
		child_menu[0].style.display='block';
		child_menu[0].style.visibility='visible';
	}
}


function show_sub()
{
	show_all_child();
	var sub = document.getElementById("sub");
	sub.style.display='block';
	sub.style.visibility='visible';

	var sub_ul = document.getElementById("sub_menu");
	sub_ul.style.display='block';
	sub_ul.style.visibility='visible';
}

function hide_sub()
{
	// hide_all_child();
	var sub = document.getElementById("sub");
	sub.style.display='none';
	sub.style.visibility='hidden';
}