function checkAge()
		{
			/* the minumum age you want to allow in */
			var min_age = 18;

			/* change "age_form" to whatever your form has for a name="..." */
			var year = parseInt(document.forms["age_form"]["year"].value);
			var month = parseInt(document.forms["age_form"]["month"].value) - 1;
			var day = parseInt(document.forms["age_form"]["day"].value);

			var theirDate = new Date((year + min_age), month, day);
			var today = new Date;

			if ( (today.getTime() - theirDate.getTime()) < 0) {
				alert("Sie sind nicht alt genug um die Seite zu betreten!");
				return false;
			}
			else {
				return true;
			}
		}