function fonddesite() {
var largeur = screen.width;
var hauteur = screen.height;
//alert(largeur);
//document.getElementById("all-theme").setAttribute("style","background: #FFFF00;");
	if (largeur <= 1024)
	{document.getElementById("all-theme").setAttribute("style","background: #37150C url(http://www.avignon-internet.fr/cairns2/templates/Cairns/images/bg-theme_1024.jpg) no-repeat;background-attachment: fixed;");}

	if (largeur == 1280)
	{document.getElementById("all-theme").setAttribute("style","background: #37150C url(http://www.avignon-internet.fr/cairns2/templates/Cairns/images/bg-theme_1280.jpg) no-repeat;background-attachment: fixed;");}
	
		if ((largeur == 1280)&&(hauteur==800))
	{document.getElementById("all-theme").setAttribute("style","background: #37150C url(http://www.avignon-internet.fr/cairns2/templates/Cairns/images/bg-theme_1280_800.jpg) no-repeat;background-attachment: fixed;");}
	
	if (largeur == 1440)
	{document.getElementById("all-theme").setAttribute("style","background: #37150C url(http://www.avignon-internet.fr/cairns2/templates/Cairns/images/bg-theme_1440.jpg) no-repeat;background-attachment: fixed;");}
	if (largeur == 1680)
	{document.getElementById("all-theme").setAttribute("style","background: #37150C url(http://www.avignon-internet.fr/cairns2/templates/Cairns/images/bg-theme_1680.jpg) no-repeat;background-attachment: fixed;");}
	if (largeur >= 1920)
	{document.getElementById("all-theme").setAttribute("style","background: #37150C url(http://www.avignon-internet.fr/cairns2/templates/Cairns/images/bg_theme_1920.jpg) no-repeat;background-attachment: fixed;height: 100%;");}



}