function init() {
  dom = (document.layers ? 'nn' : false);
  dom = (document.getElementById ? 'dom' : false);
  dom = (document.all.contenu.style ? 'ie' : false);
  if(dom== 'ie') {
     top=document.all.contenu.style.top.substring(0,document.all.contenu.style.top.length-2);
     bottom = document.all.contenu.offsetHeight;
  }
  if(dom== 'dom') {
     top=document.getElementById("contenu").style.top.substring(0,document.contenu.style.top.length-2);
     bottom = document.contenu.offsetHeight;
  }
  if(dom== 'nn') {
    top=document.contenu.style.top.substring(0,document.contenu.style.top.length-2);
    bottom = document.contenu.offsetHeight;
  }
}

function stop() {
  clearTimeout(tempo);
} 

function scroll(sens) {
  var bottom = document.all.contenu.offsetHeight;
  if(top >= 0 && sens == 1) {stop(); return '';}
  if(top <= -(bottom)+40 && sens == -1) {stop(); return '';}
  top=eval(top + pas*sens);
  if(dom=='ie') document.all.contenu.style.top = top;
  if(dom=='nn') document.contenu.style.top = top;
  if(dom=='dom') document.contenu.style.top = top;
  tempo=setTimeout('scroll('+ sens+ ')', temp);
}