parse_url($url);pathinfo($path['path'],PATHINFO_EXTENSION);

<?php 

     /** by www.phpddt.com */ 

     $url = "http://www.phpddt.com/abc/de/fg.php?id=1"; 

var_dump($url); 

echo  '<hr>'; 

     $path = parse_url($url); 

var_dump($path); 

echo  '<hr>'; 

     echo  $path['path']; 

     echo  '<hr>'; 

     echo pathinfo($path['path'],PATHINFO_EXTENSION);  //php 
?>

string 'http://www.phpddt.com/abc/de/fg.php?id=1' (length=40)

---

array
  'scheme' => string 'http' (length=4)
  'host' => string 'www.phpddt.com' (length=14)
  'path' => string '/abc/de/fg.php' (length=14)
  'query' => string 'id=1' (length=4)

---

/abc/de/fg.php

---

php