if ( ! function_exists('lcfirst'))
{
  function lcfirst($str)
  {
    if ( ! is_string($str))
    {
      throw new Exception("Subject must be of type string");
    }
    $str[0] = strtolower($str[0]);
 
    return $str;
  }
}

if ( ! function_exists('lcfirst'))
{
  function lcfirst($str)
  {
    if ( ! is_string($str))
    {
      $bt = array_pop(debug_backtrace());
      
      return '<br /><b>Warning:</b>  lcfirst() expects parameter 1 to be string, '.gettype($str)
      . ' given in <b>'.$bt['file'].'</b> on line <b>'.$bt['line'].'</b></br />';
    }
    $str[0] = strtolower($str[0]);
    
    return $str;
  }
}

Adds the function "lcfirst" if it does not exist (it was first added in PHP 5.3.0) while its counterpart, "ucfirst" was added in PHP 4.

Function \"lcfirst\" for PHP

PHP