Within the first few lines it tells the browser to stop reading the file if a certain element does not exist:

	container = document.getElementById( 'site-navigation' );
	if ( ! container ) {
		return;
	}

If you look at the source code of your page, you don’t have an element with the ID of ‘site-navigation’.

I didn’t read the other lines of that file.

You have 2 options, change the JS or change the HTML.