如何混合PHP和HTML代码？

I have a while loop and I have a HTML code inside the while loop. Inside this HTML code there is PHP code reading a variable that depends on the condition of the while loop.

This variable should be evaluated by PHP. I wrote the code below to solve this but it doesn't work.

$row[0] depends on the condition of while. My code only outputs an empty space for this variable.

<?php 
 while ($row = mysql_fetch_row($stt)) {
    $html='<div class="data">
        <?php echo nl2br($row[0]."
"); ?>
        <p><a href="">comment</a>
        <a href="">like</a>
        <a href="">share</a></p>
        <p>
        0 <span>likes</span>
        </p>
        <p>
        _____________________
        </p>
        </div>';

    echo $html;
}
?>

If you want to display something row by row, do this:

<?php 
while($row = mysql_fetch_row($stt)){

    $html="<div class='data'>" . nl2br($row[0]) . "
<p><a href="">comment</a><a href=''>like</a><a href=''>share</a></p><p>0<span>likes</span></p><p></p></div>";
    echo $html;
}
?>

>    <?php echo nl2br($row[0]."
"); ?>

this part should be outside of $html.

The interpreter on server side couldnt run.Accordin to php, this part is not a code block. It is just a text.

I found the answer of my question!!! This is the solution:

<?php 
 while($row = mysql_fetch_row($stt)){ ?>


            <div class="data">
                  <?php echo nl2br($row[0]."
"); ?>

                <p><a href="">comment</a>

                <a href="">like</a>

                <a href="">share</a></p>

                <p>

                0

                <span>likes</span>

                </p>

                <p>

                _____________________


                </p>


            </div>
<?php 
 }
 ?>