can you explain your code(Dropdown)?How is it work?

$("html").click(function() {
	$(".dropdown").hide();
});

// Any nav item that is not an only child...
$("nav ul li a:not(:only-child)").click(function(e) {
	// will be toggled.
	$(this).siblings(".dropdown").toggle();

	// Opening a new dropdown will collapse any other dropdown.
	$(".dropdown").not($(this).siblings()).hide();
	
	e.stopPropagation(); 
});