Progress bar (upload a file)

I have been trying to insert a progress bar with this tutorial

https://wordpress.org/support/topic/how-to-add-progress-bar-in-file-upload-on-submit-form

And this actualization

https://stackoverflow.com/questions/29874293/upload-progress-bar-on-contact-form-7/29948254#29948254

At the end, the progress bar only shows 0% and doesn’t change. Is this still working? How can I do?

Contact Form 7 V4.2.1

https://wordpress.org/plugins/contact-form-7/