Trigger webform reload from JS

I'd like to trigger a complete reload of a multistep ajax webform (in a block), from custom JS code.
I know it's possible because the "go back to form" link on the confirm page do this.
But I would like to do this from one of my JS function, not only when the user is on the confirm page, but also from any of the webform step.

I tried to use code from the "go back to form" button (in webform_ajax.js), but I don't really understand what is happening inside this file.

Thanx.