/*
 * eventListener compatible IE et FF
 */
function eventListener(obj, eventName, func)
{
	if (obj.addEventListener)
		obj.addEventListener(eventName, func, false);
	else if (obj.attachEvent)
		obj.attachEvent("on"+eventName, func);
}


/*
 * Scroll progressivement juqu'au haut de la page
 */
function scrollToTop(delai)
{
	if( !delai ) delai = 1;
	
	if(typeof window.pageYOffset != "undefined")
		var posTop = window.pageYOffset;
	else if(typeof document.documentElement.scrollTop != "undefined" && document.documentElement.scrollTop > 0)
		var posTop = document.documentElement.scrollTop
	else if(typeof document.body.scrollTop != "undefined")
		var posTop = document.body.scrollTop;
	else
		return true;
	
	if( posTop <= 0 ) return false;;
	
	var step = delai / 0.02;	// Nb d'étapes
	var newPos = posTop - (posTop / step);
	this.scroll(1, newPos);
	
	delai -= 0.02;
	setTimeout("scrollToTop("+delai+")",20);
	
	return false;
}



/*
 * window.onload
 */
function initAll()
{
	var scrolltop = document.getElementById("scrolltop");
	if( scrolltop )
		scrolltop.onclick = function() { return scrollToTop(0.6); };
}
eventListener(window, "load", initAll);