function first(nombre){
	for(i = 1; i <= nombre; i++) {
	    var object = document.getElementById('quadri' + i).style;
	    object.opacity = (0);
	    object.MozOpacity = (0);
	    object.KhtmlOpacity = (0);
	    object.filter = "alpha(opacity=" + 0 + ")";
	}
	if (nombre > 0) setTimeout("appel('-1','" + nombre + "')",(10000/nombre));
}

function appel(num, max) {
	num++;

	if (num >= max) {
		numb = 0;
		numa = max;
		num = -1;
	}
	else {
		numa = num;
		numb = num + 1;
	}

	if (max > 0) {
    	opacity('quadri' + numa, 'quadri' + numb, 100, 0, 1000);
    	setTimeout("appel(" + num + ",'" + max + "')",(10000/max));
    }
}

function opacity(id, idd, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) {
        for(i = opacStart; i >= opacEnd; i--) {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            j = opacStart - i;
            setTimeout("changeOpac(" + j + ",'" + idd + "')",(timer * speed));
            timer++;
        }
    } else if(opacStart < opacEnd) {
        for(i = opacStart; i <= opacEnd; i++)
            {
            setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
            j = opacEnd - i;
            setTimeout("changeOpac(" + j + ",'" + idd + "')",(timer * speed));
            timer++;
        }
    }
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
}