function ChangeOnglet(onglet, contenu) 
{   
    document.getElementById('content_1').style.display = 'none';
    document.getElementById('content_2').style.display = 'none';  
		document.getElementById('content_3').style.display = 'none'; 	      
    document.getElementById(contenu).style.display = 'block';       

    document.getElementById('tab_1').className = '';
    document.getElementById('tab_2').className = '';      
	 document.getElementById('tab_3').className = '';  
    document.getElementById(onglet).className = 'active';       
}