wordpress: loading javascript only where shortcode appears

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have an interesting conundrum. I need to load about 8 javascript files and the same number of styles for my plugin. These are only needed where ever my shortcode is ran.

I’ve tried to load them with print_styles and print_scripts but they aren’t rendering properly, plus to do so breaks xhtml validation. So at the moment they load on every page and due to the number of files needed its not feasible to leave it like this.

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On another project I wrote a function into my plugin’s index.php file that would take the current page, search it for my shortcode and if found only then would it print the scripts, but this is an ugly hack.

Has anybody got any suggestions or solutions?
any help would be appreciated,
regards,
Daithi

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9 comments

  1. to answer my own question… I had it write the first time. You have to search each page to check that your shortcode is being used. This has to be done when page data is loaded and before page is displayed. To me it is complete overkill on the system, but unfortunately it is the way it is. I got this information from:
    get_shortcode_regex
    and
    old nabble

    So first:

    add_action('template_redirect','wp_my_shortcode_head');

    then:

    function wp_my_shortcode_head(){
  global $posts;
  $pattern = get_shortcode_regex(); 
  preg_match('/'.$pattern.'/s', $posts[0]->post_content, $matches); 
  if (is_array($matches) && $matches[2] == 'YOURSHORTCODE') { 
        //shortcode is being used 
  }
}

    replace ‘YOURSHORTCODE’ with the name of your shortcode and add your wp_enqueue_scripts into where it says //shortcode is being used.

  2. I read a solution in here: http://scribu.net/wordpress/conditional-script-loading-revisited.html
    Basically if using wordpress 3.3 you can enqueue your scripts in your short code function.

    function my_shortcode($atts){
    wp_enqueue_script( 'my-script', plugins_url( 'plugin_name/js/script.js' ), array('jquery'), NULL, true);

    // if you add a css it will be added to the footer
//wp_enqueue_style( 'my-css', plugins_url( 'plugin_name/css/style.css' ) );

    //the rest of shortcode functionality
}

  3. Loading Scripts and Styles Dynamically Per Page Using a Shortcode

    Advantages

    • Does not search through all the posts everytime the shortcode is called.
    • Able to add styles as well as scripts dynamically only when shortcode is on the page.
    • Does not use regexes since they tend to be slower than strstr() or strpos(). If you need to pickup args then you should use the shortcode regex mentioned above.
    • Reduces file calls

    Explanation of Code

    1. Finds the shortcodes on page using the save_post hook only when the post is not a revision and matches the specified post_type.

    2. Saves the found post ids as an array using add_option() with autoload set to yes unless the entry is already present. Then it will use update_option().

    3. Uses hook wp_enqueue_scripts to call our add_scripts_and_styles() function.

    4. That function then calls get_option() to retrieve our array of page ids. If the current $page_id is in the $option_id_array then it adds the scripts and styles.

    Please note: I converted the code from OOP Namespaced classes so I may have missed something. Let me know in the comments if I did.

    Code Example: Finding Shortcode Occurences

    function find_shortcode_occurences($shortcode, $post_type = 'page')
{
    $found_ids = array();
    $args         = array(
        'post_type'   => $post_type,
        'post_status' => 'publish',
        'posts_per_page' => -1,
    );
    $query_result = new WP_Query($args);
    foreach ($query_result->posts as $post) {
        if (false !== strpos($post->post_content, $shortcode)) {
            $found_ids[] = $post->ID;
        }
    }
    return $found_ids;
}

function save_option_shortcode_post_id_array( $post_id ) 
{
    if ( wp_is_post_revision( $post_id ) OR 'page' != get_post_type( $post_id )) {
        return;
    }
    $option_name = 'yourprefix-yourshortcode';
    $id_array = find_shortcode_occurences($option_name);
    $autoload = 'yes';
    if (false == add_option($option_name, $id_array, '', $autoload)) update_option($option_name, $id_array);
}

add_action('save_post', 'save_option_shortcode_id_array' );

    Code Example: Shortcode Dynamically Include Scripts and Styles

    function yourshortcode_add_scripts_and_styles() {
    $page_id = get_the_ID();
    $option_id_array = get_option('yourprefix-yourshortcode');
    if (in_array($page_id, $option_id_array)) {
        wp_enqueue_script( $handle, $src, $deps, $ver, $footer = true );
        wp_enqueue_style( $handle, $src , $deps);
    }
}

add_action('wp_enqueue_scripts', 'yourshortcode_add_scripts_and_styles');

  4. Just read this tutorial over here: http://scribu.net/wordpress/optimal-script-loading.html

    Seems to be the best way.

    add_action('init', 'register_my_script');
add_action('wp_footer', 'print_my_script');

function register_my_script() {
    wp_register_script('my-script', plugins_url('my-script.js', __FILE__), array('jquery'), '1.0', true);
}

function print_my_script() {
    global $add_my_script;

    if ( ! $add_my_script )
        return;

    wp_print_scripts('my-script');
}

    In this case, the script will be enqueued only if the $add_my_script
    global was set at some point during the rendering of the page.

    add_shortcode('myshortcode', 'my_shortcode_handler');

function my_shortcode_handler($atts) {
    global $add_my_script;

    $add_my_script = true;

    // actual shortcode handling here
}

    So, the script will be added if [myshortcode …] was found in any of
    the posts on the current page.

  5. Load Scripts and Styles if Post/Page has Short Code

    The best solution is to load the files into the page header if, and only if, the current post or page has the short code inside its content. And that’s exactly what the following function does:

    function flip_register_frontend_assets() 
{

    //register your scripts and styles here

    wp_register_style('pp_font','plugin_styles.css', null, null, 'all');

global $post;

    //check whether your content has shortcode

    if(isset($post->post_content) && has_shortcode( $post->post_content, 'your-
shortcode')){

    //Enqueue your scripts and styles here 

     wp_enqueue_style( 'pp_font');

 }
 }

    Simply place this function inside of one of your plugin files and you’re good to go.
    You will need to replace [your-shortcode] with the short code you want to search for, and you will also need to replace plugin_styles.css with your stylesheet name.

  6. You can just use this code to check if the shortcode is implemented in page content or in sidebar widgets.

    <?php

if ( shortcode_exists( 'gallery' ) ) {
    // The [gallery] short code exists.
}

?>

  7. I use WordPress Version 5.4 with OOP style of code i dont know if this affect why none of the above solutions didn’t work for me so i come up with this solution:

    public function enqueue_scripts() {
 global $post;
 //error_log( print_r( $post, true ) );
 //error_log( print_r(  $post->post_content, true ) );
 //error_log( print_r(  strpos($post->post_content, '[YOUR_SHORTCODE]'),true));

 if ( is_a( $post, 'WP_Post' ) && strpos($post->post_content, '[YOUR_SHORTCODE]') ) 
 {
     wp_register_style('my-css', $_css_url);
     wp_register_script('my-js', $_js_url);
 }
}

    Hope this help someone.

  8. How many pages are these scripts going to be loaded on? Would it be feasible to maintain an array of pages, and only load the scripts/stylesheets when the current page is in the array?

    Otherwise, without scanning the code there is no way to do this, as WP doesn’t even know the shortcode exists until well into the page load.

  9. BraedenP is right, I’m pretty sure there is no way to detect shortcode usage at the execution time of wp_enqueue_scripts / when the stylesheets load.

    Is there any reason you must do this in 8 files? One would just be more efficient, then it may not be a problem to load it on every page.

    You could consider a PHP stylesheet solution that only executes certain styles if needed. A css.php file may resemble:

    <?php
header("content-type: text/css");
/* You can require the blog header to refer to WP variables and make queries */
//require '../../../wp-blog-header.php';
$css = '';
$css .= file_get_contents('style.css');
/* Consider using GET variables or querying a variable in the WP database to determine which stylesheets should be loaded. You could add an option to the backend that allows a stylesheet to be turned on or off. */
if($condition1 == TRUE) $css .= file_get_contents('condition1.css');
if($condition2 == TRUE) $css .= file_get_contents('condition2.css');
?>

    Less scripts and less stylesheets means less http requests and a faster load time.