// Declare required variables
var fadeTimer = false;
var fadeSpeed =  75;
var fadeImgInterval = 2000;
var fadeImgArray = new Array();
var fadeImgCounter = 1;
var prevImgCounter = 0;


/**
 * Unfade the current image and fade the next image in the global array fadeImgArray.
 * 
 * @param int transparentValue defines the css alpha transparency value for the current image
 */
function fadeImage(transparencyValue) {
	// Stop the current fade timer
	stopFader();
	
	var prevObj = DHTMLObj(fadeImgArray[prevImgCounter]);
	var obj = DHTMLObj(fadeImgArray[fadeImgCounter]);
	if (obj && prevObj) {
		obj.className = 'updateImgTransparency_' + transparencyValue;
		prevObj.className = 'updateImgTransparency_' + (100-transparencyValue);
	}
	
	// Increase the transparency value
	transparencyValue += 20;
	if (transparencyValue <= 100) {
		fadeTimer = setTimeout("fadeImage(" + transparencyValue + ")",fadeSpeed);
	} else {
		// Increase the counter
		prevImgCounter = fadeImgCounter;
		fadeImgCounter = (fadeImgCounter >= fadeImgArray.length -1) ? 0 : fadeImgCounter + 1;
		
		// Start a timer for the next fade
		fadeTimer = setTimeout("fadeImage(0)",fadeImgInterval);
	}
}
  

/**
 * Load the image array with images to use in the fade
 */
function loadImageArray() {
	for (i=0; i<8; i++) {
		fadeImgArray[i] = 'img_fader_' + i;
	}
}


/**
 * Start the fader that will loop through all images given in the global array fadeImgArray.
 */
function startFader() {
	loadImageArray();
	fadeTimer = setTimeout("fadeImage(0)",fadeImgInterval);
}


/**
 * Stop the fader by clearing the fader timeout
 */
function stopFader() {
	// Clear the old timeout to avoid multiple fades
	if (fadeTimer) {
		clearTimeout(fadeTimer);
	}
}