function modificationCheckBox(nomChamp) {
	var champ = document.forms[0].elements[nomChamp];
	var champCache = champ.name.substring(0, champ.name.lastIndexOf("Bis"));
	if (champ.checked) {
		document.forms[0].elements[champCache].value="true";
	} else {
		document.forms[0].elements[champCache].value="false";
	}
}