- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$blah = 'Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)';
if (preg_match('/MSIE ([0-9]*(?:\\.[0-9]*)?)([0-9.]*);/', $blah, $matches)){
var_dump($matches);
}