/* Opacité pour texte */

/* PARTIE FADE IN/OUT POUR LOGO */
function fadeEffect(img1, img2, millisec){
	//if an element is invisible, make it visible, else make it ivisible
	if(document.getElementById(img1).style.opacity == 0){
		opacity(img1, 0, 100, millisec);
		opacity(img2, 100, 0, millisec);
	} else {
		opacity(img1, 100, 0, millisec);
		opacity(img2, 0, 100, millisec);
	} 
}

/* PARTIE FADE IN/OUT POUR ARTICLES */
function fadeArticle(img1, img2, millisec){
	opacityArticle(img1, 0, 100, millisec);
	opacityArticle(img2, 100, 0, millisec);
}


function opacity(id, 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));
			timer++;
		}
	} else if(opacStart < opacEnd){
		for(i = opacStart; i <= opacEnd; i++){
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	}
}

function opacityArticle(id, opacStart, opacEnd, millisec){
	opacity(id, opacStart, opacEnd, millisec);
	if(opacEnd<50)
		document.getElementById(id).style.display="none";
	else
		document.getElementById(id).style.display="block";
}

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