You may want to parse the query string into an array. 

<?php
/**
 * Similar to parse_str. Returns false if the query string or URL is empty. Because we're not parsing to 
 * variables but to array key entries, this function will handle ?[]=1&[]=2 "correctly."
 *
 * @return array Similar to the $_GET formatting that PHP does automagically.
 * @param string $url A query string or URL 
 * @param boolean $qmark Find and strip out everything before the question mark in the string
*/
function parse_query_string($url, $qmark=true)
{
    if ($qmark) {
        $pos = strpos($url, "?");
        if ($pos !== false) {
            $url = substr($url, $pos + 1);
        }
    }
    if (empty($url))
        return false;
    $tokens = explode("&", $url);
    $urlVars = array();
    foreach ($tokens as $token) {
        $value = string_pair($token, "=", "");
        if (preg_match('/^([^\[]*)(\[.*\])$/', $token, $matches)) {
            parse_query_string_array($urlVars, $matches[1], $matches[2], $value);
        } else {
            $urlVars[urldecode($token)] = urldecode($value);
        }
    }
    return $urlVars;
}

/**
 * Utility function for parse_query_string. Given a result array, a starting key, and a set of keys formatted like "[a][b][c]" 
 * and the final value, updates the result array with the correct PHP array keys.
 *
 * @return void
 * @param array $result A result array to populate from the query string
 * @param string $k The starting key to populate in $result
 * @param string $arrayKeys The key list to parse in the form "[][a][what%20ever]"
 * @param string $value The value to place at the destination array key
*/
function parse_query_string_array(&$result, $k, $arrayKeys, $value)
{
    if (!preg_match_all('/\[([^\]]*)\]/', $arrayKeys, $matches))
        return $value;
    if (!isset($result[$k])) {
        $result[urldecode($k)] = array();
    }
    $temp =& $result[$k];
    $last = urldecode(array_pop($matches[1]));
    foreach ($matches[1] as $k) {
        $k = urldecode($k);
        if ($k === "") {
            $temp[] = array();
            $temp =& $temp[count($temp)-1];
        } else if (!isset($temp[$k])) {
            $temp[$k] = array();
            $temp =& $temp[$k];
        }
    }
    if ($last === "") {
        $temp[] = $value;
    } else {
        $temp[urldecode($last)] = $value;
    }
}

/**
* Breaks a string into a pair for a common parsing function. 
*
* The string passed in is truncated to the left half of the string pair, if any, and the right half, if anything, is returned.
*
* An example of using this would be:
* <code>
* $path = "Account.Balance";
* $field = string_pair($path);
* 
* $path is "Account"
* $field is "Balance"
*
* $path = "Account";
* $field = string_pair($path);
*
* $path is "Account"
* $field is false
* </code>
*
* @return string The "right" portion of the string is returned if the delimiter is found.
* @param string $a A string to break into a pair. The "left" portion of the string is returned here if the delimiter is found.
* @param string $delim The characters used to delimit a string pair
* @param mixed $default The value to return if the delimiter is not found in the string
* @desc 
*/
function string_pair(&$a, $delim='.', $default=false)
{
    $n = strpos($a, $delim);
    if ($n === false)
        return $default;
    $result = substr($a, $n+strlen($delim));
    $a = substr($a, 0, $n);
    return $result;
}

?>