I filled out a profile to 80%, hit back accidentally (Safari keyboard shortcuts for back/forwards are apparently the same as default macOS beginning/end of line

I filled out a profile to 80%, hit back accidentally (Safari keyboard shortcuts for back/forwards are apparently the same as default macOS beginning/end of line text editing shortcuts? And a textfield I thought had focus didnt'? Not 100% sure.), and found the entire form empty again. If there ever is a place where state saving using sth like sessionStorage is vital, it's such long-form forms.