wp_enqueue_scripts, wp_register_scripts, wp_print_scripts: i'm confused

Question

• I've been reading up a bit on this subject, but the more I read - the more confused I get.

• Can someone explain to me in short what's the exact difference between wp_enqueue_scripts, wp_register_scripts and wp_print_scripts?

• For example, I have the following code in my functions.php - and it's working, but I do not understand why I can not use wp_print_scripts for the stylesheets, whereas the code still works if I use wp_enqueue_scripts for the javascript files:

  add_action('wp_print_scripts', 'add_my_js');
  function add_my_js(){
      if(!is_admin()){
          wp_enqueue_script('default',  get_bloginfo('stylesheet_directory').'/js/default.js', array('jquery'));
      }
  }
  
  add_action('wp_enqueue_scripts', 'add_my_stylesheet');
  function add_my_stylesheet() {
      wp_register_style('default', get_bloginfo( 'stylesheet_url'));
      wp_enqueue_style( 'default');
  }
  

Answer 1

wp_print_scripts is the action that runs when scripts are output to the template. wp_register_script and wp_enqueue_script are functions for registering/enqueueing scripts to be output when wp_print_scripts runs.

you can't register or enqueue styles in the wp_print_scripts action hook because styles have already been output in the wp_print_styles hook, which runs before wp_print_scripts.

refer to the action reference to see the order things are executed in in a request:

22. wp_head
23. wp_enqueue_scripts
24. wp_print_styles
25. wp_print_scripts