(function () { window.hyphaChanged = false; let textarea = document.querySelector('.edit-form__textarea'); let form = document.querySelector('.edit-form'); let warnBeforeClosing = function (ev) { if (!window.hyphaChanged) return; ev.preventDefault(); return ev.returnValue = 'Are you sure you want to exit? You have unsaved changes.'; }; textarea.addEventListener('input', function () { window.hyphaChanged = true; }); form.addEventListener('submit', function () { window.hyphaChanged = false; }); window.addEventListener('beforeunload', warnBeforeClosing); })();