Separating HTML And PHP Code

I separate my code (not limited to PHP) from HTML in one of 2 ways:

1) use of includes (e.g. require_once()):

<?php require_once('header.php'); ?>
        <table>
            <tr>
                <td>
                    Hello Nairaland!!
                 </td>
             </tr>
        </table>
<?php require_once('footer.php'); ?>

2) beginning my code tabbed over once from the line and my HTML tabbed over 2ce from the line.  In other words, take PHP for example:

<?php
    $uri = $_SERVER['REQUEST_URI'];    //to obtain what comes after www.nairaland.com in address bar above
   
    if(strchr($uri, "topic=35738") {        //does the uri contain the string, "topic=35738"?
?>
        <table>
            <tr>
                <td>
                    Hello Nairaland!!
                 </td>
             </tr>
        </table>
<?php
    } else {
?>
        <table>
            <tr>
                <td>
                    Hello Nigeriaworld!!
                 </td>
             </tr>
        </table>
<?php
    }//if
?>

Of course, for #2, I could hv printed out the strings without using tables.  I just wanted to illustrate indentation 

I hope this helps