jQuery.validator.addMethod("time", function(value, element) {
		return this.optional(element) || /^([01][0-9])|(2[0123]):([0-5])([0-9])$/.test(value);
	}, "Please enter a valid time, between 00:00 and 23:59"
);

jQuery.validator.addMethod("positivenumber", function(value, element) {
		value = value.replace(",",".");
		return this.optional(element) || (value > 0);
	}, "Please enter a positive value"
);