function opacite(img, etat, over, out) {
	var tab;
	tab = new Array();
	
	tab[10] = '0.1';
	tab[20] = '0.2';
	tab[30] = '0.3';
	tab[40] = '0.4';
	tab[50] = '0.5';
	tab[60] = '0.6';
	tab[70] = '0.7';
	tab[80] = '0.8';
	tab[90] = '0.9';
	tab[100] = '1';
	
	if (img != undefined && etat != undefined) {
		over = (over != undefined ? over : 50);
		out = (out != undefined ? out : 100);
		
		if (img.style.filter != undefined) {
			img.style.filter='alpha(opacity='+(etat == true ? over : out)+')';
		}
		else {
			img.style.opacity = (etat == true ? tab[over] : tab[out]);
		}
	}
}