Inside a PHP script I have this:
echo <<<EOD
<script type="text/javascript">
document.getElementById('my_element_id').innerHTML='Do stuff';
</script>
EOD;
Can I add PHP inside the JavaScript? Replace the "Do stuff" part with PHP code? If yes, how do I do it?
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).
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.
foo is not defined as a JavaScript variable.
$anyphpvariable contains no new lines or ' characters (which it doesn't in this example, but that isn't a robust solution). @h2ooooooo's answer covers this and is much better.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
