Question

I have a file called: file.php

contained in this file is the following code:

<script type="text/javascript">
        //....
        var sumJS = 10;
    <?php $sumPHP = sumJS  ?>
</script>
    <?php echo "Sum = " . $sumPHP ?>

How can I assign sumJS for $sumPHP?

If I would like to make this conversely then I would write:

  $sumPHP = 10;
<script type="text/javascript">
    var sumJS;
    sumJS = <?php echo $sumPHP ?>;
    alert(sumJS);
</script>

But how can I re-make this for my problem?

Answer 1

$sumPHP is a server-side value, which will be evaluated on the server. Then the server generates page content and sent it to the client. Then browsers receive the page content and evaluate client-side value sumJS.

So you can never assign sumJS for $sumPHP because $sumPHP is calculated before sumJS.

But can do this to show the page:

<?php echo "Sum = "?><script type="text/javascript">document.write(sumJS);</script>

or rather

<script type="text/javascript">document.write('Sum = ' + sumJS);</script>