<php>

 <?php
function age($date_of_birth){
$dob =date('Y-m-d', strtotime($date_of_birth));
$age = date('Y') - date('Y', strtotime($dob));
if (date('md') < date('md', strtotime($dob))) {
$age--;
}
return $age;
}

?>

</php>

Therefore, as an example:

See the example below to use the function

 <php>

<?php

$age=age('2-09-1950');