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++;
		}
	}
}

//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 + ")";
}

function shiftOpacity(id, millisec) {
	//if an element is invisible, make it visible, else make it ivisible
	if(document.getElementById(id).style.opacity == 0) {
		opacity(id, 0, 100, millisec);
	} else {
		opacity(id, 100, 0, millisec);
	}
}

function blendimage(divid, imageid, imagefile, millisec) {
	var speed = Math.round(millisec / 100);
	var timer = 0;
	
	//set the current image as background
	document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")";
	
	//make image transparent
	changeOpac(0, imageid);
	
	//make new image
	document.getElementById(imageid).src = imagefile;

	//fade in image
	for(i = 0; i <= 100; i++) {
		setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed));
		timer++;
	}
}

function currentOpac(id, opacEnd, millisec) {
	//standard opacity is 100
	var currentOpac = 100;
	
	//if the element has an opacity set, get it
	if(document.getElementById(id).style.opacity < 100) {
		currentOpac = document.getElementById(id).style.opacity * 100;
	}

	//call for the function that changes the opacity
	opacity(id, currentOpac, opacEnd, millisec)
}
<!--
    if(document.images)
    {

	  Bt_precedent_Bt_precedent_on = new Image();
      Bt_precedent_Bt_precedent_on.src = 'img/precedent.jpg';
      Bt_precedent_Bt_precedent_over = new Image();
      Bt_precedent_Bt_precedent_over.src = 'img/precedent_over.jpg';
	  Bt_precedent_Bt_precedent_clic = new Image();
      Bt_precedent_Bt_precedent_clic.src = 'img/precedent_clic.jpg';
	  
	  imagemap2_default_challenger = new Image();
      imagemap2_default_challenger.src = 'img/menu_challenger.jpg';
      imagemap2_domaine = new Image();
      imagemap2_domaine.src = 'img/menu_challenger_domaine.jpg';
	  imagemap2_modalite = new Image();
      imagemap2_modalite.src = 'img/menu_challenger_modalite.jpg';
	  imagemap2_reference = new Image();
      imagemap2_reference.src = 'img/menu_challenger_reference.jpg';
	  imagemap2_domaine_clic = new Image();
      imagemap2_domaine_clic.src = 'img/menu_challenger_domaineclic.jpg';
	  imagemap2_modalite_clic = new Image();
      imagemap2_modalite_clic.src = 'img/menu_challenger_modaliteclic.jpg';
	  imagemap2_reference_clic = new Image();
      imagemap2_reference_clic.src = 'img/menu_challenger_referenceclic.jpg';
	  
	  imagemap2_default_connaitre = new Image();
      imagemap2_default_connaitre.src = 'img/menu_connaitre.jpg';
      imagemap2_fondateur = new Image();
      imagemap2_fondateur.src = 'img/menu_connaitre_fondateur.jpg';
	  imagemap2_societe = new Image();
      imagemap2_societe.src = 'img/menu_connaitre_societe.jpg';
	  imagemap2_contacter = new Image();
      imagemap2_contacter.src = 'img/menu_connaitre_contacter.jpg';
	  imagemap2_fondateur_clic = new Image();
      imagemap2_fondateur_clic.src = 'img/menu_connaitre_fondateurclic.jpg';
	  imagemap2_societe_clic = new Image();
      imagemap2_societe_clic.src = 'img/menu_connaitre_societeclic.jpg';
	  imagemap2_contacter_clic = new Image();
      imagemap2_contacter_clic.src = 'img/menu_connaitre_contacterclic.jpg';
	  
	  imagemap2_default_rejoindre = new Image();
      imagemap2_default_rejoindre.src = 'img/menu_rejoindre.jpg';
      imagemap2_poste = new Image();
      imagemap2_poste.src = 'img/menu_rejoindre_poste.jpg';
	  imagemap2_collegue = new Image();
      imagemap2_collegue.src = 'img/menu_rejoindre_collegue.jpg';
	  imagemap2_vision = new Image();
      imagemap2_vision.src = 'img/menu_rejoindre_vision.jpg';
	  imagemap2_poste_clic = new Image();
      imagemap2_poste_clic.src = 'img/menu_rejoindre_posteclic.jpg';
	  imagemap2_collegue_clic = new Image();
      imagemap2_collegue_clic.src = 'img/menu_rejoindre_collegueclic.jpg';
	  imagemap2_vision_clic = new Image();
      imagemap2_vision_clic.src = 'img/menu_rejoindre_visionclic.jpg';
	  
	  imagemap2_default_accueil = new Image();
      imagemap2_default_accueil.src = 'img/menu_accueil.jpg';
      imagemap2_connaitre = new Image();
      imagemap2_connaitre.src = 'img/menu_accueil_connaitre.jpg';
	  imagemap2_challenger = new Image();
      imagemap2_challenger.src = 'img/menu_accueil_challenger.jpg';
	  imagemap2_rejoindre = new Image();
      imagemap2_rejoindre.src = 'img/menu_accueil_rejoindre.jpg';
	  imagemap2_connaitre_clic = new Image();
      imagemap2_connaitre_clic.src = 'img/menu_accueil_connaitreclic.jpg';
	  imagemap2_challenger_clic = new Image();
      imagemap2_challenger_clic.src = 'img/menu_accueil_challengerclic.jpg';
	  imagemap2_rejoindre_clic = new Image();
      imagemap2_rejoindre_clic.src = 'img/menu_accueil_rejoindreclic.jpg';
	  
	  imagemap2_default_modalite = new Image();
      imagemap2_default_modalite.src = 'img/menu_modalite.jpg';
      imagemap2_forfait = new Image();
      imagemap2_forfait.src = 'img/menu_modalite_forfait.jpg';
	  imagemap2_assistance = new Image();
      imagemap2_assistance.src = 'img/menu_modalite_assistance.jpg';
	  imagemap2_RetD = new Image();
      imagemap2_RetD.src = 'img/menu_modalite_R&D.jpg';
	  imagemap2_forfait_clic = new Image();
      imagemap2_forfait_clic.src = 'img/menu_modalite_forfaitclic.jpg';
	  imagemap2_assistance_clic = new Image();

      imagemap2_assistance_clic.src = 'img/menu_modalite_assistanceclic.jpg';
	  imagemap2_RetD_clic = new Image();
      imagemap2_RetD_clic.src = 'img/menu_modalite_R&Dclic.jpg';
	  
	  imagemap2_default_web_sgbd = new Image();
      imagemap2_default_web_sgbd.src = 'img/menu_web_sgbd.jpg';
      imagemap2_java = new Image();
      imagemap2_java.src = 'img/menu_web_sgbd_java.jpg';
	  imagemap2_libre = new Image();
      imagemap2_libre.src = 'img/menu_web_sgbd_libre.jpg';
	  imagemap2_dot_net = new Image();
      imagemap2_dot_net.src = 'img/menu_web_sgbd_dot_net.jpg';
	  imagemap2_java_clic = new Image();
      imagemap2_java_clic.src = 'img/menu_web_sgbd_javaclic.jpg';
	  imagemap2_libre_clic = new Image();
      imagemap2_libre_clic.src = 'img/menu_web_sgbd_libreclic.jpg';
	  imagemap2_dot_net_clic = new Image();
      imagemap2_dot_net_clic.src = 'img/menu_web_sgbd_dot_netclic.jpg';
	  
	  imagemap2_default_poste = new Image();
      imagemap2_default_poste.src = 'img/menu_poste.jpg';
      imagemap2_pjava = new Image();
      imagemap2_pjava.src = 'img/menu_poste_java.jpg';
	  imagemap2_pbi = new Image();
      imagemap2_pbi.src = 'img/menu_poste_BI.jpg';
	  imagemap2_pdot_net = new Image();
      imagemap2_pdot_net.src = 'img/menu_poste_dot_net.jpg';
	  imagemap2_pjava_clic = new Image();
      imagemap2_pjava_clic.src = 'img/menu_poste_javaclic.jpg';
	  imagemap2_pbi_clic = new Image();
      imagemap2_pbi_clic.src = 'img/menu_poste_BIclic.jpg';
	  imagemap2_pdot_net_clic = new Image();
      imagemap2_pdot_net_clic.src = 'img/menu_poste_dot_netclic.jpg';
	  
	  imagemap2_default_domaine = new Image();
      imagemap2_default_domaine.src = 'img/menu_domaine.jpg';
      imagemap2_web = new Image();
      imagemap2_web.src = 'img/menu_domaine_web_sgbd.jpg';
	  imagemap2_bi = new Image();
      imagemap2_bi.src = 'img/menu_domaine_BI.jpg';
	  imagemap2_mobilite = new Image();
      imagemap2_mobilite.src = 'img/menu_domaine_mobilite.jpg';
	  imagemap2_web_clic = new Image();
      imagemap2_web_clic.src = 'img/menu_domaine_web_sgbdclic.jpg';
	  imagemap2_bi_clic = new Image();
      imagemap2_bi_clic.src = 'img/menu_domaine_BIclic.jpg';
	  imagemap2_mobilite_clic = new Image();
      imagemap2_mobilite_clic.src = 'img/menu_domaine_mobiliteclic.jpg';
	  
    }

    function rollOver(iName,iState)
    {
      if(document.images)
      {
        document.images[iName].src = eval(iName + '_' + iState + '.src');
      }
    }
	function rollOver2(iName,iState,d)
    {
      if(document.images)
      {
        document.getElementById(d).images[iName].src = eval(iName + '_' + iState + '.src');
      }
    }
	function HideContent(d) 
	{
		document.getElementById(d).style.display = "none";
	}
	function ShowContent(d) 
	{
	document.getElementById(d).style.display = "block";
	}
	
  // -->
var menu = null;
function init_menu()
{
	menu = document.getElementById('menu');
	var li = menu.getElementsByTagName('li'), i = li.length;
	while (i--) li[i].onmouseover = showMenu;
	menu.onmouseout = timeout;
	menu.onmouseover = cleartimer;
}

var timer = null;
function timeout()
{
	timer = setTimeout('hideMenus(menu, null)', 500);
}

function cleartimer()
{
	if (timer)
	{
		clearTimeout(timer);
		timer = null;
	}
}

function showMenu()
{
	var ul = this.parentNode;
	while (ul)
	{
		if (ul.tagName.toLowerCase() == 'ul')
		{
			hideMenus(ul, this);
			break;
		}

		ul = ul.parentNode;
	}

	ul = this.firstChild;
	while (ul)
	{
		if (ul.nodeType == 1 && ul.tagName.toLowerCase() == 'ul')
		{
			ul.style.display = 'block';
			ul.style.visibility = ''; // necessary for IE
			break;
		}

		ul = ul.nextSibling;
	}
}

function hideMenus(level, skipli)
{
	var stack = [level], i = 0, li, j, el, tag;
	do
	{
		li = stack[i].childNodes, j = li.length;
		while (j--)


		{
			el = li[j];
			if (el.nodeType == 1 && el != skipli)
			{
				tag = el.tagName.toLowerCase();
				if (tag == 'li')
				{
					stack[i++] = el;
				}
				else if (tag == 'ul' && el.style.display == 'block')
				{
					stack[i++] = el;
					el.style.display = 'none';
					el.style.visibility = 'hidden'; // necessary for IE
				}
			}
		}
	}
	while (i--);
}

// JavaScript Document