note 97991 modified in function.htmlspecialchars by danbrown

Here's a simple function I wrote for parsing form data.

It checks if it's an array and it is recursive (it calls itself).

It also decodes things that have already been encoded so it doesn't change & to &

[In this version,] I found it easier to use a regular expression to check and see if any previously encoded data exists, then decode it repeatedly until there is none left, then re-encode it.

<?php
function formspecialchars($var)
	{
		$pattern = '/&(#)?[a-zA-Z0-9]{0,};/';
		
		if (is_array($var)) {    // If variable is an array
			$out = array();      // Set output as an array
			foreach ($var as $key => $v) {      
				$out[$key] = formspecialchars($v); 		// Run formspecialchars on every element of the array and return the result. Also maintains the keys.
			}
		} else {
			$out = $var;
			while (preg_match($pattern,$out) > 0) {
				$out = htmlspecialchars_decode($out,ENT_QUOTES);   	
			}		 					
			$out = htmlspecialchars(stripslashes(trim($out)), ENT_QUOTES,'UTF-8',true); 	// Trim the variable, strip all slashes, and encode it
			
		}
		
		return $out;
	}
?>

--was--
Updated my form data parser. I found it easier to use a regular expression to check and see if any previously encoded data exists, then decode it repeatedly until there is none left, then re-encode it.

<?php
function formspecialchars($var)
	{
		$pattern = '/&(#)?[a-zA-Z0-9]{0,};/';
		
		if (is_array($var)) {    // If variable is an array
			$out = array();      // Set output as an array
			foreach ($var as $key => $v) {      
				$out[$key] = formspecialchars($v); 		// Run formspecialchars on every element of the array and return the result. Also maintains the keys.
			}
		} else {
			$out = $var;
			while (preg_match($pattern,$out) > 0) {
				$out = htmlspecialchars_decode($out,ENT_QUOTES);   	
			}		 					
			$out = htmlspecialchars(stripslashes(trim($out)), ENT_QUOTES,'UTF-8',true); 	// Trim the variable, strip all slashes, and encode it
			
		}
		
		return $out;
	}
?>

http://php.net/manual/en/function.htmlspecialchars.php