//global variables for possible browser types
var isIE4 = new Boolean(false);
var isNav4 = new Boolean(false);
var isNew = new Boolean(false);

//set the global variables according to browser type
isIE4 = navigator.family =="ie4" && navigator.version == 4;
isNav4 = navigator.family =="nn4";
isNew = ((navigator.family == "ie4" && navigator.version > 4) || navigator.family == "gecko");

var diff = new String();
var style = new String();
var prevmenu = "";

if (isIE4){
	diff = ".all";
	style = "style";
} else if (isNav4){
	diff =".layers";
	style = "";
}

//change the state of the menu
function visChange(menu,state){
	//if a previous menu was open, then hide it
	if (prevmenu != ""){
		doChange(prevmenu, "hidden")
		} 
	//make hovered-over menu visible
	doChange(menu,state)
		//assign the menu to prevmenu so it closes when hovering over a different menu
		prevmenu = menu;
}

function doChange(menu,state){
	if (isIE4 || isNav4) {
		eval("document" + diff + "['" + menu + "']" + style + 
			".visibility = '" + state + "'");
	} else if (isNew){
		var elemID = document.getElementById(menu);
		elemID.style.visibility = state;
	}
}