Question

Under what conditions can I put PHP into Javascript code? Is it always ok? Is it just a bad idea? I am surprised I have not seen it more.

For example, I came across this..

$('#thumbnail').imgAreaSelect({aspectRatio: '<?php echo $thumb_height/$thumb_width;?>', onSelectChange:preview}); 

..which was in an onpage script element. I’m not so experienced, but I was just surprised that I had never seen mixed js/php before. But can you put PHP in .js files as well? If I set the file extension to .php, will the file be parsed?

Answer 1

You can put PHP code into *.js files but you need to tell the webserver to also execute the PHP interpreter on *.js files. Something like this should be in your httpd.conf

<IfModule php5_module>
    AddType application/x-httpd-php .php .php5 .js

    ...
</IfModule>

A better solution is to just rename your *.js files to *.js.php or just *.php. The browsers won’t mind and the PHP interpreter will also get executed on those.