// ============================================
// JavaScript to fade in/out background images


// global variables
var speed = 30;
var dir  = '/images/homepage/';

function swapBackground() {

  // fade out the imagefader layer leaving new image
  var timer = 0;
  for(i = 100; i >= 0; i=i-2) {
    setTimeout("changeOpac(" + i + ",'imageFader')",(timer * speed));
    timer++;
  }
  
  // reset the layers and pre-load next image
  setTimeout("resetBackground1()",(timer * speed)+500);
  setTimeout("resetBackground2()",(timer * speed)+3000);


  // schedule next fade
  setTimeout("swapBackground()",10000);

}


// reset the background layers
function resetBackground1() {

  // set image fader to the current image and full opacity
  document.getElementById('imageFader').style.backgroundImage = 'url(' + dir + photos[curImageNum] + ')';
  
  // get new image for rotation
  curImageNum++;
  if(curImageNum > maxImageNum) { curImageNum = 0; }
}

function resetBackground2() {
  changeOpac(100,'imageFader');

// set background to new image
  document.getElementById('page').style.backgroundImage = 'url(' + dir + photos[curImageNum] + ')';

}

 
// change the opacity for different browsers
function changeOpac(opacity, id) {
  var object = document.getElementById(id).style;
  object.opacity = (opacity / 100);
  object.MozOpacity = (opacity / 100);
  object.KhtmlOpacity = (opacity / 100);
  object.filter = "alpha(opacity="+ opacity + ")";
} 


// pre-load first new image and set timer to start process
setTimeout("resetBackground1()",1000);
setTimeout("resetBackground2()",1500);
setTimeout("swapBackground()",10000);