Why won't wp_enqueue_script work within any plugin file?

I have a plugin, from which within one of the files I am trying to include a JS file the proper way:

function inveroak_feed_search_enqueue() {
    wp_enqueue_script('inveroak-feed-search', plugin_dir_url(__file__).'assets/js/search.js');
}
add_action('wp_enqueue_scripts', 'inveroak_feed_search_enqueue');

Further down the file I am referencing this function from an input field like this:

<input onkeyup="inveroak_feed_search(this)" />

However, whenever I press any key within the input, all I see is this in the console (and the JS file isn't being loaded also).

Uncaught ReferenceError: inveroak_feed_search is not defined at HTMLInputElement.onkeyup ((index):120)

Contents of search.js if it helps:

function inveroak_feed_search(element) {
    (function($) {
        var value = $(element).val();
        $(".inveroak-feed-container").each(function() {
            if ($(this).find(".op-name,.op-pin,.op-toolbox li").text().toLowerCase().search(value.toLowerCase()) > -1) {
                $(this).show();
            } else {
                $(this).hide();
            }
        });
    })(jQuery);
}

Can anyone help why this JS file isn't loading?