Mixing php and javascript -- under what conditions?

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?

The title and the actual question do not match, not even close. — Arjan
– Arjan, Commented Mar 9, 2012 at 10:49

Basti · Accepted Answer · 2012-03-09 10:53:31Z

6

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.

answered Mar 9, 2012 at 10:53

Basti

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Romi Halasz · Accepted Answer · 2012-03-09 11:16:18Z

0

Mixing JS with PHP is usually avoided due to debugging difficulties and/or poor code readability (like mixing PHP with HTML). It is, however, possible. But a safer approach might be to pass the PHP value to a function, or set the PHP value to a global JS variable, and use that instead. Maybe something like this:

    //JS code
    var value = <?php echo ($thumb_height/$thumb_width);?>

....

    $('#thumbnail').imgAreaSelect({aspectRatio: value, onSelectChange:preview});

This way it will be much easier to read. Have a great day.

answered Mar 9, 2012 at 11:16

Romi Halasz

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11 Comments

Romi Halasz Over a year ago

I disagree. PHP is not considered a template engine. And if mixing it with HTML and/or JS is possible, that doesn't mean that it's a must.

Your Common Sense Over a year ago

You need more experience and/or research. PHP is a leading template engine nowadays. It can do the same what Smarty or XSLT does but without Smarty or XSLT. Why use anything else? Why mixing PHP with HTML is a no-no but Smarty with HTML is all right? What's the difference?

Romi Halasz Over a year ago

Would you be so kind as to share some links on this topic, since obviously I need more experience?...And if you don't know the answer to your own question, I think you are the one who needs more experience and/or research.

Your Common Sense Over a year ago

Zend framework for example framework.zend.com/manual/en/zend.view.scripts.html.

Basti Over a year ago

Nice link but I personally prefer smarty for my templates and I personally don't know anybody who would write templates with PHP. It's just terrible to read.

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Your Common Sense · Accepted Answer · 2012-03-09 11:27:58Z

0

Under what conditions can I put PHP into Javascript code?

Under no conditions. That would be impossible and useless.
You can can put only contrary - JS code into PHP. In other words you can make PHP output whatever text, which can be valid HTML, JS, XML, whatever.
Once sent to the browser, this text will be interpreted accordingly, but with not a trace of PHP in it.

It is always OK as long as PHP represents display logic only.

So, you put PHP in .js files only if it would be actually PHP files.

answered Mar 9, 2012 at 11:27

Your Common Sense

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Comments

Howard Schutzman · Accepted Answer · 2012-03-09 17:13:10Z

0

The code you presented is a very reasonable way to dynamically generate javascript in the web page returned by the web server.

So, for example, if $thumb_height was 100 and $thumb_width was 10, the web server would return a web page containing the following javascript:

$('#thumbnail').imgAreaSelect({aspectRatio: '10', onSelectChange:preview});

If, on another call to the page, $thumb_height was 24 and $thumb_width was 6 the web page returned by the server would be:

$('#thumbnail').imgAreaSelect({aspectRatio: '4', onSelectChange:preview});

You can use php to dynamically generate any part of a web page, both the html and the javascript.

answered Mar 9, 2012 at 17:13

Howard Schutzman

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