Write a PHP script to remove a part of a string from the beginning

PHP is a server scripting language, and It is a powerful tool for making interactive and dynamic Web-pages. I have used WampServer 2.2 for following example..

<?php
$substring = 'admin@';
$str1 = 'admin@techstudy.org';
if (substr($str1, 0, strlen($substring)) == $substring) 
{
 $str1 = substr($str1, strlen($substring));
}
echo $str1."\n";
?>

Result:

techstudy.otg