function calculCotisation()
{
  const tabTr = document.querySelector( '#table-facture' ).querySelector( 'tbody' ).querySelectorAll( 'tr' );
  let total = 0;

  for ( let i = 0; i < activites.length; i++ ) 
  {
    if ( tabTr[ i ]. cells[ 2 ].childNodes[ 0 ].checked )
    {
      tabTr[ i ].cells[ 3 ].innerHTML = activites[ i ].prix;
      total += activites[ i ].prix;
    }
    else
    {
      tabTr[ i ].cells[ 3 ].innerHTML = 0;
    } 
  }
  document.querySelector( '#total' ).innerHTML = total;
}