Can I write PHP inside JavaScript inside PHP? [duplicate]

Answer 1

Can be done like:

<?php 
$anyphpvariable='foo';
echo <<<EOD 
    <script type="text/javascript">
       document.getElementById('my_element_id').innerHTML=$anyphpvariable;

    </script>
EOD;
?>

Anything from php can be assign to JS and its good practice. But not JS can assign anything to PHP.

Answer 2

Yes, but I can only get what you want if I place the code after the relevant HTML. You can echo scripts...for example, this will work:

<div id="footer">Hey</div>
<?php 
$myVar = 'Hello';
echo "<SCRIPT>
   document.getElementById('footer').innerHTML = '$myVar';
</SCRIPT>";
?> // You will see Hello in the footer

but this will not work:

<?php 
$myVar = 'Hello';
echo "<SCRIPT>
   document.getElementById('footer').innerHTML = '$myVar';
</SCRIPT>";
?>
<div id="footer">Hey</div>// You will see Hey in the footer

As a side note, these other functions/methods will work too:

$myVar = 'Hi';
echo "<SCRIPT>
    alert('$myVar');
</SCRIPT>";//Alerts 'Hi'

$myVar = 'home.php';
echo "<SCRIPT>
    location = '$myVar';
</SCRIPT>";//Takes you to home.php

$myVar = 'hi';
echo "<SCRIPT>
    myFunction('$myVar');
</SCRIPT>";//calls myFunction with argument $myVar

Answer 3

First of all, it should be noted that this has nothing to do with javascript. You could have any form of text. Your actual question is how to use a variable inside of a heredoc.

Heredoc is defined as the following:

Nowdocs are to single-quoted strings what heredocs are to double-quoted strings. A nowdoc is specified similarly to a heredoc, but no parsing is done inside a nowdoc. The construct is ideal for embedding PHP code or other large blocks of text without the need for escaping.

Meaning that since this works:

$name = 'Foo';

echo "My name is $name"; // Using double quotes so variables get expanded

Then this also works:

$name = 'Foo';

echo <<<EOD
    My name is <strong>$name</strong>
EOD;  // Using heredoc so variables get expanded

Essentially meaning that yes, as long as you put your 'Do stuff' content into a variable first. Note that if you use more advanced variables/arrays, it's a good idea to do a $array = json_encode($array) before pasting it into JS code (imagine if $name was The Boss's Wife - then the apostrophe would ruin your JS if you don't encode it).

DEMO