将简单的PHP代码包含到Javascript中

Question

How do I make this work? I've googled and even saw some examples here on Stackoverflow which show this kind of coding, but it doesn't work for me.

<script type="text/javascript">
  var infoClass = "";
  infoClass = <?php echo('test'); ?>;
  alert(infoClass);
</script>

The alert box displays empty box.

Answer 1

Your resulting JS code will be:

infoClass = test;

As there's no variable test , this won't work right. You need to wrap it in quotes, just like any other string:

<script type="text/javascript">
  var infoClass = "";
  infoClass = '<?php echo('test'); ?>';
  alert(infoClass);
</script>

You can also use json_encode() , which may be handy for more complicated situations where you're echoing out arrays, objects, etc.:

infoClass = <?php echo json_encode('test'); ?>;

Answer 2

Make sure your code is in a .php file, or inside a file that has an extension that will be parsed by PHP.

Also make sure the printed content will be inside of a string ( "" )