what does WordPress wp_localize_script do? [closed]

Question

can someone explain me what wp_localize_script() do? I don't understand what it does in the first place even I have read it in the WP Codex.

Answer 1

It lets you use PHP data in the client by printing out a JavaScript object. From the Codex:

Localizes a script, but only if script has already been added. Can also be used to include arbitrary Javascript data in a page.

You use like so:

// Register script as per Codex instructions.
// It doesn't have to contain anything but the file must exist
wp_register_script('handle', get_template_directory_uri() .'/js/dummy.js');

// Send data to client
wp_localize_script('handle', 'Data', array(
  'url' => home_url(),
));

This will print an object in JavaScript:

<script type='text/javascript'>
/* <![CDATA[ */
var Data = {"url":"http://..."};
/* ]]> */
</script>

Now in the client you can access that data:

console.log(Data.url);

It's very useful when you're building plugins so you can separate your client from your server logic instead of mixing JS and PHP all in the same file.