How to check characters in a string are alphanumeric in php

[Saman]

This verifies if a PHP string contains characters other than letters or numbers using the PHP function ereg. This PHP code snippet can be useful for form input where you only want users to input alpha numeric characters.

Code: Select all

<?php 

// Example 1 

$text = "onlyalphanumericcharacters012345"; 

if (ereg('[^A-Za-z0-9]', $text)) { 
  echo "This contains characters other than letters and numbers"; 
} 
else { 
  echo "This contains only letters and numbers";     
} 

// Example 2 

$text = "mixedcharacters012345&../@"; 

if (ereg('[^A-Za-z0-9]', $text)) { 
  echo "This contains characters other than letters and numbers"; 
} 
else { 
  echo "This contains only letters and numbers";     
} 

?>