validate Gender in a text box

[onofej]

Please could someone tell me the best way to wrtite this in PHP i am validating gender in a text box i do not want to use radio button. at present my code is like this but not working

if(preg_match("/gender/i",$field))
        {
          if(!preg_match("/^M,F $/",$value))
          {
            $errors[] = "$value is not a valid gender.";
          }
        }

Could some tell me how to make sure value is either M OR F user inputed in box

[deceptikon]

Why a text box? That forces you to validate essentially unchecked input. If you don't want to use radio buttons, how about a dropdown menu with M or F?

[cereal]

In addition to deceptikon. Supposing you have a form field named gender which sends the data with POST method:

<input type="text" name="gender" />

This can work:

if(!in_array(strtolower(trim($_POST['gender'])),array('m','male','f','female'))
{
    $errors[] = ''; # message
}

if nothing is matching the array values then it sends an error. This can work also with select or radio buttons which, in my opinion, are better solutions.

@onofej

Do you have DB?

If so, you can used what cereal wrote to check the valve either M or F

<input type="text" name="gender" />