/* BannerCycle.js */

var bannerFilenameArray = new Array ( 
"BannerLazarusDrop700W.jpg",
"BannerFluteHarpDrop700W.jpg",
"BannerEgmontDrop700W.jpg",
"BannerDonizettiDrop700W.jpg",
"BannerMahlerDrop700W.jpg",
"BannerHaydnDrop700W.jpg", 
"BannerElgarDrop700W.jpg",
"BannerStandDrop700W.jpg"
 );
 
var opacity = 10;
 
var bannerImageArray = new Array();

var bannerCount = -1;
var bannerStep = 10;

function initBannerCycle()
{
    preloadImages();
    changeBanner();
    fadeIn();
}


function preloadImages() 
{
     var i = 0;
     
     // start preloading
     for(i=0; i<bannerFilenameArray.length; i++)      
     {     
        var filename = bannerFilenameArray[i];
        var pathname = "images/banner/" + filename;
              
        bannerImageArray[i] = new Image();
        bannerImageArray[i].src = pathname;
     }

}

function changeBanner()
{
    bannerCount = bannerCount + 1;
    if ( bannerCount >= bannerFilenameArray.length ) bannerCount = 0;
    
    var filename = bannerFilenameArray[bannerCount];
    var element =  document.getElementById("banner");
        
    element.src = bannerImageArray[bannerCount].src;
} 

function fadeOut()
{
    var element =  document.getElementById("banner");
   
    opacity = opacity - bannerStep;
    element.style.opacity = opacity/10;
    element.style.filter = 'alpha(opacity=' + opacity*10 + ')';    
    
    if ( opacity <= 0 ) 
    {
        changeBanner();
        fadeIn();
    }
    else
    {
        setTimeout("fadeOut()", 10);
    } 
}

function fadeIn()
{
    var element =  document.getElementById("banner");
 
    opacity = opacity + bannerStep;
    element.style.opacity = opacity/10;
    element.style.filter = 'alpha(opacity=' + opacity*10 + ')';    
    
    if ( opacity >= 10 ) 
    {
        setTimeout("fadeOut()", 3000);
    }
    else
    {
        setTimeout("fadeIn()", 50);
    } 
}