function cacher(){
  objFondLight = document.getElementById('fond_light');
  objAchat = document.getElementById('achat_box');
  objReservation = document.getElementById('reservation_box');
  objBonCadeau = document.getElementById('bon_cadeau_box');
  objFondLight.style.display = 'none';
  objAchat.style.display = 'none';
  objReservation.style.display = 'none';
  objBonCadeau.style.display = 'none';
}
     
function montreAchat(){
  var objFondLight = document.getElementById('fond_light');
  var objAchat = document.getElementById('achat_box');
  var arrayPageSize = getPageSize();
  var arrayPageScroll = getPageScroll();

  objFondLight.style.height = (arrayPageSize[1] + 'px');
  objFondLight.style.display = 'block';
  objAchat.style.display = 'block';
}
function montreReservation(){
  
  var objFondLight = document.getElementById('fond_light');
  var objReservation = document.getElementById('reservation_box');
  var arrayPageSize = getPageSize();
  var arrayPageScroll = getPageScroll();
  objFondLight.style.height = (arrayPageSize[1] + 'px');
  objFondLight.style.display = 'block';
  objReservation.style.display = 'block';
}
function montreBonCadeau(){
  var objFondLight = document.getElementById('fond_light');
  var objBonCadeau = document.getElementById('bon_cadeau_box');
  var arrayPageSize = getPageSize();
  var arrayPageScroll = getPageScroll();

  objFondLight.style.height = (arrayPageSize[1] + 'px');
  objFondLight.style.display = 'block';
  objBonCadeau.style.display = 'block';
}

function getPageSize(){
  var xScroll, yScroll;
  if (window.innerHeight && window.scrollMaxY) {	
    xScroll = document.body.scrollWidth;
	yScroll = window.innerHeight + window.scrollMaxY;
  }
  else if (document.body.scrollHeight > document.body.offsetHeight){ 
    xScroll = document.body.scrollWidth;
	yScroll = document.body.scrollHeight;
  }
  else {
    xScroll = document.body.offsetWidth;
	yScroll = document.body.offsetHeight;
  }
  var windowWidth, windowHeight;
  if (self.innerHeight) {	
    windowWidth = self.innerWidth;
	windowHeight = self.innerHeight;
  }
  else if (document.documentElement && document.documentElement.clientHeight) {
    windowWidth = document.documentElement.clientWidth;
	windowHeight = document.documentElement.clientHeight;
  }
  else if (document.body) { 
    windowWidth = document.body.clientWidth;
	windowHeight = document.body.clientHeight;
  }	
  if(yScroll < windowHeight){
    pageHeight = windowHeight;
  }
  else { 
    pageHeight = yScroll;
  }
  if(xScroll < windowWidth){	
    pageWidth = windowWidth;
  }
  else {
    pageWidth = xScroll;
  }
  arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
  return arrayPageSize;
}
      
function getPageScroll(){
  var yScroll;
  if (self.pageYOffset) {
    yScroll = self.pageYOffset;
  }
  else if (document.documentElement && document.documentElement.scrollTop){	 
    yScroll = document.documentElement.scrollTop;
  }
  else if (document.body) {// Tout autres qu'Explorers
    yScroll = document.body.scrollTop;
  }
  arrayPageScroll = new Array('',yScroll) 
  return arrayPageScroll;
}

function initialisation(){
/*  var objBody = document.getElementsByTagName("body").item(0); // on recupere le body en objet
  var objOverlay = document.createElement("div") ;   // on crée un div 
  objOverlay.setAttribute('id','overlay');           // on lui donne le id overlay
  objOverlay.onclick = function () {cacher(); return false;}  // on lui definit une fonction sur le onclick
  objOverlay.style.display = 'none';    // pas d'affichage
  objOverlay.style.position = 'absolute';  
  objOverlay.style.top = '0';
  objOverlay.style.left = '0';
  objOverlay.style.zIndex = '90';
  objOverlay.style.width = '100%';  // sur toute la largeur
  objBody.insertBefore(objOverlay, objBody.firstChild);  // on définit overlay comme premier enfant de body
  var arrayPageSize = getPageSize();
  var arrayPageScroll = getPageScroll();

  var objLightbox = document.createElement("div");   // je crée l'objet lightbox
  objLightbox.setAttribute('id','lightbox');         // son id c 'lightbox' ^^
  objLightbox.style.display = 'none';                // pas d'affichage
  objLightbox.style.position = 'absolute';          
  objLightbox.style.zIndex = '100';	
  objBody.insertBefore(objLightbox, objOverlay.nextSibling);  // je le met juste apres overlay
  */
  var objFondLight = document.getElementById('fond_light');
  var arrayPageSize = getPageSize();
  var arrayPageScroll = getPageScroll();

  objFondLight.style.width = (arrayPageSize[2] + 'px');
}

function addLoadEvent(func){	
  var oldonload = window.onload;
  if (typeof window.onload != 'function'){
    window.onload = func;
  }
  else {
    window.onload = function(){
	  oldonload();
	  func();
      }
  }
}

addLoadEvent(initialisation);