Switch case in Javascript does not work properly

console.log('['+DETAILS[6]+']');
switch (DETAILS[6]) {
case 'TERMINE' :
    CLASSE='statut_ok';
    console.log('TERMINE => '+CLASSE);
break;
case 'EXECUTION_EN_COURS' :
    CLASSE='statut_wa';
    console.log('EXECUTION_EN_COURS => '+CLASSE);
break;
case 'undefined' :
    PARAMS[4]='-1';
    CLASSE='statut_no';
    console.log('undefined => '+CLASSE);
break;
default :
    PARAMS[4]=(parseInt(PARAMS[4])+1).toString();
    CLASSE='statut_ko';
    console.log('default => '+CLASSE);
break;
}