function subnavShow() {
	if(!document.getElementById) return false;
	if(!document.getElementById("subnav_bt")) return false;
	if(!document.getElementById("subnav_list")) return false;
	var btn = document.getElementById("subnav_bt");
	var list = document.getElementById("subnav_list");
	btn.onmouseover = function() {
		list.style.display = "block";
	}
	btn.onmouseout = function() {
		list.style.display = "none";

	}
	list.onmouseover = function() {
		list.style.display = "block";

	}
	list.onmouseout = function() {
		list.style.display = "none";

	}
	if(!document.getElementById("subnav_bt_btm")) return false;
	if(!document.getElementById("subnav_list_btm")) return false;
	var btn_btm = document.getElementById("subnav_bt_btm");
	var list_btm = document.getElementById("subnav_list_btm");
	btn_btm.onmouseover = function() {
		list_btm.style.display = "block";
	}
	btn_btm.onmouseout = function() {
		list_btm.style.display = "none";

	}
	list_btm.onmouseover = function() {
		list_btm.style.display = "block";

	}
	list_btm.onmouseout = function() {
		list_btm.style.display = "none";

	}
}

function addLoadEvent(func) {
	var oldonload = window.onload;
	if( typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			oldonload();
			func();
		}
	}
} 

addLoadEvent(subnavShow);