[HILFE] JavaScript vür Alters Überprüfung

<script language="JavaScript">
function check_age(form) {
 if (form.value < 18) {
 alert("Du bist zu jung");
 } else { 
 alert("Perfekt :-)");
 }
}
</script>

<form name="check_age">
Alter: <input type="text" size="5" name="age">
<br />
<input type="button" value="Submit" onclick="Validate(this.form.age)">
</form>

<form name="check_age">
Alter: <input type="text" size="5" name="age">
<br />
<input type="button" value="Submit" onclick="check_age(this.form.age)">
</form>