function ChangeOnglet1(onglet, contenu) 
{   
    document.getElementById('content_1').style.display = 'none';
    document.getElementById('content_2').style.display = 'none';      
    document.getElementById(contenu).style.display = 'block';       

    document.getElementById('tab_1').className = '';
    document.getElementById('tab_2').className = '';      
    document.getElementById(onglet).className = 'active';       
}