Detect url contains query string ?

parse_url function is used to break the url components

This function parses a URL and returns an associative array containing any of the various components of the URL that are present.

• scheme - e.g. http
• host
• port
• user
• pass
• path
• query - after the question mark ?
• fragment - after the hashmark #

The following code reads url query string and convert into array.

<?php
$queries= parse_url($_SERVER['REQUEST_URI'],PHP_URL_QUERY);
 // splits url query string into array
$queries_elements = split('&', $queries);
//converts to array
for($i = 0; $i != sizeof($queries_elements); $i++)
    {
    $queries = split('=', $queries_elements[$i]);
    //assigns to new array
    $params[$queries[0]]=$queries[1];
    }
var_dump($params);
?> 

More examples 
echo parse_url('http://example.com?mode=edit&id=34', PHP_URL_QUERY);
Output : 'mode=edit&id=34'
echo parse_url('http://example.com?mode=edit&id=34#user', PHP_URL_FRAGMENT)
Output : 'user'
echo parse_url('http://example.com', PHP_URL_SCHEME);
Output : 'http'
echo parse_url('http://example.com?mode=edit&id=34#user', PHP_URL_HOST);
Output : 'example.com'
echo parse_url('http://example.com:88?id=34', PHP_URL_PORT);
Output : 88