How can I change my javascript after it has been enqueued? [closed]

Writing my first plugin, trying to make it as simple as possible. I put simplistic functions in the javascript just so it would let me know it was there. Afterward I changed the methods in the javascript. WP doesn’t recognize that the javascript changed. It looks like this:

function registerjs()
{
    wp_register_script('pcjavascript', plugins_url('PerformantCalendar.js', __FILE__));
    //wp_dequeue_script('pcjavascript');
    //echo "ichi";
    wp_enqueue_script('pcjavascript');
    echo "ni";
}

add_action('wp_enqueue_scripts', 'registerjs');

The javascript file looks like this:

function monthNext()
{
    alert("In the haunted javascript file");
}

function monthPrev()
{
    alert("This also works");
}

Now if I change the message in the alert box, it still alerts by the first message. I’ve tried dequeueing the script, inactivating and reactivating the plugin. I’m missing something. Can somebody help?

Your JS is being cached. In development, just empty your cache. But for production code, it’s helpful to note that wp_enqueue_scripts() takes a version argument that lets you set a script version number which is then added to the URL as a query string for cache busting purposes. (side note, the wp_register_script function is actually built into the wp_enqueue_script function, so you only need the one.)

function registerjs()
{
    wp_enqueue_script('pcjavascript', plugin_dir_url(__FILE__) . 'PerformantCalendar.js', array(), '1.0', false);
}

add_action('wp_enqueue_scripts', 'registerjs');

This will append “?ver=1.0” to the end of the url in your page’s source. Then, after updating the .js file, change the version number:

function registerjs()
{
    wp_enqueue_script('pcjavascript', plugin_dir_url(__FILE__) . 'PerformantCalendar.js', array(), '1.1', false);
}

add_action('wp_enqueue_scripts', 'registerjs');

This will append “?ver=1.1” instead, causing the browser to see it as a different file, and it will request it from the server instead of using a cached copy. More information about wp_enqueue_scripts() can be found here.