// JavaScript Document

var timeout   = 250; // milliseconds
var fadeSpeed = 500;  // milliseconds
var useFade   = true;

var timers = new Array();

var state = new Array();

// prevent multiple timers from making the fade flicker
var lastOpacity = new Array();

// detect MSIE

var msie = false;
if( navigator.appName == "Microsoft Internet Explorer" ) msie = true;

// entry point: set element to visible and clear its timers
function setMenu( id )
{
    var e = document.getElementById(id);
    e.style.visibility = "visible";
    state[id] = true;
    setOpacity( id, 1 );
    if(timers[id]) {
        clearTimeout(timers[id]);
        timers[id] = undefined;
     }
}

// set element to hidden and reset its opacity

function hideMenu( id )
{
    var e = document.getElementById(id);
    state[id] = false;
    e.style.visibility = "hidden";
    if(useFade) setOpacity( id, 1 );
}


function clearMenu( id )
{
    if(useFade) timers[id] = setTimeout( 'fadeMenu( "' + id + '" )', timeout );
    else timers[id] = setTimeout( 'hideMenu( "' + id + '" )', timeout );
}

// if MSIE
function setOpacity( id, value )
{
    var e = document.getElementById(id);

    if(state[id]) value = .90;  
    else if(lastOpacity[id] && (lastOpacity[id] < value)) value = lastOpacity[id];  // prevents flicker if multiple timers set
    
    if(msie) e.style.filter = 'alpha(opacity=' + value * 100 + ')'; // MSIE value
    else e.style.opacity = (value); 

    if( value == 0 ) hideMenu( id ); // when all faded, reset the menu state
    lastOpacity[id] = value;
}


function fadeMenu ( id )
{
    var start = 0;
    var end = 0;
    var s = Math.round( fadeSpeed / 25 );   // fade in 25ms increments
    var timer = 0;
    var i;

    state[id] = false;

    for( i = s; i >= 0 ; i-- ) {
        setTimeout( "setOpacity('" + id + "'," + ( i / s ) + ")", timer++ * fadeSpeed / s )
    }
}