function decompte()
 {
 var time= document.chrono.time.value;
 document.chrono.time.value=eval(time-1);
 
 window.setTimeout("decompte()",1000);
 if(time==1)
  {
  document.chrono.time.value = "0";
  //alert("Temps écoulé!");history.go(0);
  }
 }