pretix_original/src/pretix/static/pretixbase/js/ajaxpending.js

var check = function () {
    $.getJSON(location.href + '&ajax=1', function (data, status) {
        if (data.redirect) {
            location.href = data.redirect;
        } else {
            window.setTimeout(check, 500);
        }
    });
}
window.setTimeout(check, 500);