Parse url. Break down a url to get the parameters / arguments. Very helpful....

parse-url.php

<?php

$url = 'http://usr:[email protected]:81/mypath/myfile.html?a=b&b[]=2&b[]=3#myfragment'; 
if ($url === unparse_url(parse_url($url))) { 
  print "YES, they match!\n"; 
} 

function unparse_url($parsed_url) { 
  $scheme   = isset($parsed_url['scheme']) ? $parsed_url['scheme'] . '://' : ''; 
  $host     = isset($parsed_url['host']) ? $parsed_url['host'] : ''; 
  $port     = isset($parsed_url['port']) ? ':' . $parsed_url['port'] : ''; 
  $user     = isset($parsed_url['user']) ? $parsed_url['user'] : ''; 
  $pass     = isset($parsed_url['pass']) ? ':' . $parsed_url['pass']  : ''; 
  $pass     = ($user || $pass) ? "$pass@" : ''; 
  $path     = isset($parsed_url['path']) ? $parsed_url['path'] : ''; 
  $query    = isset($parsed_url['query']) ? '?' . $parsed_url['query'] : ''; 
  $fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : ''; 
  return "$scheme$user$pass$host$port$path$query$fragment"; 
}