forms - I want to use regular expression in php -

i want know how give user error on form validation if < or > used in form fields. here script:

$pattern = "<,>";  if (preg_match($pattern, $_post["u"])) {     exit("this illegal, error!!!"); }

use [<>]

if (preg_match('/[<>]/', $_post["u"])) {     // illegal char }

however there no need use regular expressions. can use strpos:

if (strpos($_post["u"], '<') !== false || strpos($_post["u"], '>') !== false) {     // illegal char }

Call