Else if is working fine, Else is working fine as well, but the initial if statement is not working. Can someone share what this noob is doing wrong - thanks in advance

<code>
<HTML>
<HEAD>
<SCRIPT>
var age = parseInt(prompt("Please enter your age:"))
if (age < 21)
{
alert("Sorry, you are too young to enter")
}
else if (age > 21)
{
alert("Sorry, you are too old to enter")
}
else (age == 21)
{
alert ("Welcome to our exclusive club");
location.href = "http://www.houstonian.com"
}

</SCRIPT>
</HEAD>
<BODY>
</BODY>
</HTML>
</code>