var indice = 0, prochain, opacite = 1, pas = 0.1, interval = 100;
var images;

function diaporama()
{
	images = document.getElementById("contenu").getElementsByTagName("img");
	
	images[0].style.opacity = 1;
	prochain = (indice+1 < images.length) ? indice+1 : 0;
	setInterval("degrader()", 2000);
}

function degrader()
{
	images[indice].style.opacity = opacite-pas;
	images[prochain].style.opacity = 1+pas-opacite;

	opacite -= pas;

	if(opacite > pas)
		setTimeout("degrader()", interval);

	else
	{
		images[indice].style.opacity = 0;
		images[prochain].style.opacity = 1;
		opacite = 1;

		if(++indice == images.length)
			indice = 0;

		prochain = (indice+1 < images.length) ? indice+1 : 0;
	}
}