Alert box showing "asdf"

[marc-farre]

After adding a comment to a global content and submitting a form containing this comment, I got an alert box:

Isn't it a forgotten test in humhub.linkpreview.js?

        this.$.closest('form').on('submit', function () {
            alert('asdf');
        });

[gevorgmansuryan]

seems already 6 years it works like this :)