// mettre un minimum de 4 images !!!

		var coef = 0.05 ; // avancement de l'opacité
		var temps = 50 ; // temps entre chaque changement d'opacité
		var temps_pause = 2000 ; // temps d'attente entre 2 changements d'images
		var nombre_image = 4 ; // nombre d'images a faire bouger
		var prefix_image = 'images/expertises/'; // chemin + prefix du nom des images
		var prefix_image2 = 'images/chantier/'; // chemin + prefix du nom des images
		var suffix_image = '.jpg' ; // suffix + '.extension' du nom des images
		// pas touche
		var indice = 2; // les 2 premiere image sont deja charger dans le HTML, on commence a la 3eme
		var indice2 = 2; // les 2 premiere image sont deja charger dans le HTML, on commence a la 3eme
		var isIE = navigator.userAgent.toLowerCase().indexOf('msie')!=-1 ;
		var img1 = null;
		var img2 = null ;
		var imag1 = null;
		var imag2 = null ;
		var sens = 1;
		var sens2 = 1;
		var tabImg; // tab contenant les images
		var tabImag;

		function prechargerImg(){
		tabImg = new Array(nombre_image);
		for (i=0; i<=nombre_image -1; i++){
		tabImg[i]=new Image();
		tabImg[i].src = prefix_image+(i+1)+suffix_image;
		}
		}
		function init()
		{
		img1 = document.getElementById("defilement1") ;
		img2 = document.getElementById("defilement2") ;

		prechargerImg();
		change_opacity();
		}
		
		function change_opacity()
		{
		var opacity1 = 0 ;
		var opacity2 = 0 ;
		if (isIE) // for IE
		{ opacity1 = parseFloat(img1.filters.alpha.opacity);
		opacity2 = parseFloat(img2.filters.alpha.opacity);
		}
		else // for mozilla
		{ opacity1 = parseFloat(img1.style.MozOpacity);
		opacity2 = parseFloat(img2.style.MozOpacity);
		}

		if (sens)
		{ if (isIE) // for IE
		{ img1.filters.alpha.opacity = opacity1 + coef * 100;
		img2.filters.alpha.opacity = opacity2 - coef * 100;
		}
		else // for Mozilla
		{ img1.style.MozOpacity = opacity1 + coef;
		img2.style.MozOpacity = opacity2 - coef;
		}
		}
		else
		{
		if (isIE) // for IE
		{ img1.filters.alpha.opacity = opacity1 - coef * 100;
		img2.filters.alpha.opacity = opacity2 + coef * 100;
		}
		else // for Mozilla
		{ img1.style.MozOpacity = opacity1 - coef;
		img2.style.MozOpacity = opacity2 + coef;
		}
		}

		if (isIE) // for IE
		{ opacity1 = parseFloat(img1.filters.alpha.opacity);
		opacity2 = parseFloat(img2.filters.alpha.opacity);
		}
		else // for mozilla
		{ opacity1 = parseFloat(img1.style.MozOpacity);
		opacity2 = parseFloat(img2.style.MozOpacity);
		}

		// on fait varié le sens d'opacité du bazar
		if (opacity2 <= 0)
		{ img2.src=tabImg[indice++].src;
		sens = 0;
		if (indice == (tabImg.length)) indice=0;
		window.setTimeout("change_opacity()",temps_pause) ; // attente
		return 0;
		}
		else if (opacity1 <= 0)
		{ img1.src=tabImg[indice++].src;
		sens = 1;
		if (indice == (tabImg.length)) indice=0;
		window.setTimeout("change_opacity()",temps_pause) ; // attente
		return 0;
		}
		window.setTimeout("change_opacity()",temps) ; // recursion toutes les x millisec
		}

	//--------------------------------------------------------------	
		function prechargerImg2(){
		tabImag = new Array(nombre_image);
		for (j=0; j<=nombre_image -1; j++){
		tabImag[j]=new Image();
		tabImag[j].src = prefix_image2+(j+1)+suffix_image;
		}
		}
		function init2()
		{
		imag1 = document.getElementById("defilement3") ;
		imag2 = document.getElementById("defilement4") ;

		prechargerImg2();
		change_opacity2();
		}
		
		
		function change_opacity2()
		{
		var opacity3 = 0 ;
		var opacity4 = 0 ;
		if (isIE) // for IE
		{ opacity3 = parseFloat(imag1.filters.alpha.opacity);
		opacity4 = parseFloat(imag2.filters.alpha.opacity);
		}
		else // for mozilla
		{ opacity3 = parseFloat(imag1.style.MozOpacity);
		opacity4 = parseFloat(imag2.style.MozOpacity);
		}

		if (sens2)
		{ if (isIE) // for IE
		{ imag1.filters.alpha.opacity = opacity3 + coef * 100;
		imag2.filters.alpha.opacity = opacity4 - coef * 100;
		}
		else // for Mozilla
		{ imag1.style.MozOpacity = opacity3 + coef;
		imag2.style.MozOpacity = opacity4 - coef;
		}
		}
		else
		{
		if (isIE) // for IE
		{ imag1.filters.alpha.opacity = opacity3 - coef * 100;
		imag2.filters.alpha.opacity = opacity4 + coef * 100;
		}
		else // for Mozilla
		{ imag1.style.MozOpacity = opacity3 - coef;
		imag2.style.MozOpacity = opacity4 + coef;
			}
		}

		if (isIE) // for IE
		{ opacity3 = parseFloat(imag1.filters.alpha.opacity);
		opacity4 = parseFloat(imag2.filters.alpha.opacity);
		}
		else // for mozilla
		{ opacity3 = parseFloat(imag1.style.MozOpacity);
		opacity4 = parseFloat(imag2.style.MozOpacity);
		}
		// on fait varié le sens d'opacité du bazar
		if (opacity4 <= 0)
		{ imag2.src=tabImag[indice2++].src;
		sens2 = 0;
		if (indice2 == (tabImag.length)) indice2=0;
		window.setTimeout("change_opacity2()",temps_pause) ; // attente
		return 0;
		}
		else if (opacity3 <= 0)
		{ imag1.src=tabImag[indice2++].src;
		sens2 = 1;
		if (indice2 == (tabImag.length)) indice2=0;
		window.setTimeout("change_opacity2()",temps_pause) ; // attente
		return 0;
		}
		window.setTimeout("change_opacity2()",temps) ; // recursion toutes les x millisec
		
		}