AMD Modules http://learn.elgg.org/en/stable/guides/javascript.html

Hello Jerome !

I have read but cannot figure out which module should be used for this code

Might work. Save the following as /views/default/js/blogvideocover.js

define(function (require) {
    var $ = require('jquery');
    var elgg = require('elgg');

    var BVC = {
        save: function() {
            var form = $('form#blog-post-edit');
            elgg.action('blogvideocover/save', {
                data: {
                guid: form.find('input[name=guid]').val(),
                url: form.find('input[name=blog_video_cover]').val()
            },
            success: function() {
                elgg.system_message(elgg.echo('blogvideocover:update'));
            }
            });
        },
        init: function() {
            var form = $('form#blog-post-edit');
            var delay = (function() {
                var timer = 0;
                return function(callback, ms) {
                    clearTimeout (timer);
                    timer = setTimeout(callback, ms);
                };
            })();
            $('input#blog_video_cover_id').keyup(function() {
                delay(elgg.blogvideocover.save, 500 );
            });
        }
    };
    elgg.register_hook_handler('init', 'system', BVC.init);
}

and then add in the form view at the beginning

elgg_require_js('blogvideocover');

No promise that it works though! The point is: you have to write the AMD module yourself, i.e. rewrite the existing JS code as an AMD module. With the AMD module you also don't need to use elgg_extend_view anymore to load the module because this is done explicitely with elgg_require_js within the view (and only this view) requiring the JS code to be avaiable.

iionly thank you very much for your help

No guarantee it will work. Might still contain bugs you have to fix. One bug is that you need to change

elgg.blogvideocover.save

into

BVC.save