Empty cart in session after exiting order steps?

Question

Online shopping

there is a problem, customers wanted to reset the order steps when the user left the order steps pages, an implementation was made, the principle was:
js listens to the 'unload' event and sets
the cookie the cookie is not set if the user clicks the next steps, well, or any navigation inside the steps (stupidly hardcode by elements with a link to 'click' and clearing the 'unload' listener) the server looks at the cookie, well, and clears
the steps, in fact .
there is a form from the steps, well, when posting, the page reloads, well, you understand ..
Googled, I could not find how others did it.
What other mechanisms exist for such functionality?