var DIAPO_TIME = 2000;
var INTERVAL_TRANSITION = 50;

var elems, active_elem, fade_status, opacity, timer;

function getImgs(elementId) {
	var res = new Array();
	var elem = document.getElementById(elementId).firstChild;
	while (elem != null) {
		if (elem.tagName == 'A' && elem.firstChild.tagName == 'IMG') {
			res[res.length] = elem.firstChild;
		}
		elem = elem.nextSibling;
	}
	return res;
}

function init_fade_partenaires() {
	elems = getImgs('fade_partenaires');
	for (var i=0 ; i<elems.length ; i++) {
		elems[i].style.display = 'block';
		elems[i].style.top = ((document.getElementById('fade_partenaires').offsetHeight - elems[i].offsetHeight)/2) + "px";
		elems[i].style.left = ((document.getElementById('fade_partenaires').offsetWidth - elems[i].offsetWidth)/2) + "px";
		elems[i].style.display = 'none';
	}
	active_elem = 0;
	start_fade();
}

function start_fade() {
	var elem = elems[active_elem];
	elem.style.filter = 'Alpha(opacity=0, finishopacity=0, style=3)';
	elem.style.opacity = '0';
	elem.style.display = 'block';
	fade_status = 0;
	opacity = 0;
	window.clearInterval(timer);
	timer = window.setInterval('fade()', INTERVAL_TRANSITION);
}

function fade() {
	var elem = elems[active_elem];
	switch (fade_status) {
		case 0:
			opacity += 5;
			elem.style.filter = 'Alpha(opacity='+opacity+', finishopacity='+opacity+', style=3)';
			elem.style.opacity = opacity / 100;
			if (opacity >= 100) {
				window.clearInterval(timer);
				fade_status = 1;
				timer = window.setTimeout('fade('+elem.id+')', DIAPO_TIME);
			}
			break;
		case 1:
			window.clearTimeout(timer);
			fade_status = 2;
			timer = window.setInterval('fade('+elem.id+')', INTERVAL_TRANSITION);
			break;
		case 2:
			opacity -= 5;
			elem.style.filter = 'Alpha(opacity='+opacity+', finishopacity='+opacity+', style=3)';
			elem.style.opacity = opacity / 100;
			if (opacity <= 0) {
				window.clearInterval(timer);
				elem.style.display = 'none';
				active_elem++;
				if (active_elem >= elems.length) {
					active_elem = 0;
				}
				start_fade(elems[active_elem]);
			}
	}
}