С помощью Beacon API (
https://developer.mozilla.org/ru/docs/Web/API/Beac...)
var params = new URLSearchParams({
key : 'Key test',
values : 'Value test'
});
navigator.sendBeacon(anUrl, params);
С помощью картинки (
https://developer.mozilla.org/ru/docs/Web/API/HTML...)
var form = document.querySelector('form');
var data = new FormData(form);
var img = new Image();
img.src = 'https://example.org/form/send?' + data;
img.onload = function() {
alert(1);
};
Reference:
https://stackoverflow.com/a/26501400
https://stackoverflow.com/a/11941783
https://stackoverflow.com/a/56646623