$(document).ready(function() {

	$(".when").each(dateChange);
	$(".when").change(dateChange);

});

function dateChange() {
	var sel = "." + this.id + "date";
	if ($(this).val() != "0") {
		$(sel).removeAttr("disabled");
	}
	else {
		$(sel).attr("disabled", "disabled");
	}
}