Passing variables from php to javascript

https://stackoverflow.com/questions/23740548/how-to-pass-variables-and-data-from-php-to-javascript

<!-- snip -->
<div id="dom-target" style="display: none;">
    <?php 
        $output = "42"; //Again, do some operation, get the output.
        echo htmlspecialchars($output); /* You have to escape because the result
                                           will not be valid HTML otherwise. */
    ?>
</div>
<script>
    var div = document.getElementById("dom-target");
    var myData = div.textContent;
</script>
<!-- snip -->