<?php
function isPalindrome($String){
    /************************************************
    V2.0 - Simplified to the point of being trivial.
           Popping characters and recursing no longer occurs,
           we strip the string down and then compare it with
           the reverse.
    
    This function takes in a $String and returns true if it
      is a palindrome.
    *************************************************
    Example usage:
        $String = "Madam, I'm Adam";
        //Outputs: "Madam, I'm Adam" is a palindrome 
        if (isPalindrome($String)){
            echo "\"" . $String . "\" is a palindrome";
        }else{
            echo "\"" . $String . "\" is not a palindrome";
        }
    ***************************************************/

    $String = strtolower($String);
    $String = str_replace(array("\n","\t","\r"," "),"",$String);
    $String = ereg_replace("[^A-Za-z0-9]+","",$String);
    
    //if a string is the same as its reverse, it is a palindrome
    return ($String == strrev($String));
}
?>