Question

how to call a header file ?

Answer 1

Here is an example of how:

 
<?php include 'header.php'; ?>

<b>Sub-Page Title</b><p>

Here is the specific content of this page....<br>

<?php include 'footer.php'; ?>

Answer 2

The header string.

    There are two special-case header calls. The first is a header that starts with the string "HTTP/" (case is not significant), which will be used to figure out the HTTP status code to send. For example, if you have configured Apache to use a PHP script to handle requests for missing files (using the ErrorDocument directive), you may want to make sure that your script generates the proper status code.

    <?php
    header("HTTP/1.0 404 Not Found");
    ?>

    The second special case is the "Location:" header. Not only does it send this header back to the browser, but it also returns a REDIRECT (302) status code to the browser unless the 201 or a 3xx status code has already been set.

    <?php
    header("Location: http://www.example.com/"); /* Redirect browser */

    /* Make sure that code below does not get executed when we redirect. */
    exit;
    ?>
replace

    The optional replace parameter indicates whether the header should replace a previous similar header, or add a second header of the same type. By default it will replace, but if you pass in FALSE as the second argument you can force multiple headers of the same type. For example:

    <?php
    header('WWW-Authenticate: Negotiate');
    header('WWW-Authenticate: NTLM', false);
    ?>
http_response_code

    Forces the HTTP response code to the specified value.