<form> Valeur 1 Valeur 2 Tous </form> <script language="javascript"> function ChekBox(tous) { if (tous.checked) { document.forms[0].elements.check1.checked = true; document.forms[0].elements.check2.checked = true; } else { document.forms[0].elements.check1.checked = false; document.forms[0].elements.check2.checked = false; } } </script>