tilda + ajax (post) or XMLHttpRequest mobile don't send

Question

On the desktop version of different browsers, everything works fine, and both methods work. But on mobile, none works. Pages are fully loaded, there are no errors, everything is also loaded on the mobile version. Only data is not transferred. How can you decide?

    $(document).ready(function(){
    var user  = ''; // name
    var user2 = ''; // email
    var x     = localStorage.getItem("memberarea_profile");
    var x2    = JSON.parse(x);
    var x3    = window.location; // current url
    var dataString = 'email='+user2+'&name='+ user+'&page='+ x3;

    $.ajax({
        type: 'POST',
        url: 'https://server',
        crossDomain: true,
        data: dataString,
        success: function(responseData, textStatus, jqXHR) {
        },
        error: function(xhr, status, error) {
            var err = eval("(" + xhr.responseText + ")");
            alert(err.Message);
        }
    });

    function getXmlHttp(){
        var xmlhttp;
        try {
            xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (E) {
        xmlhttp = false;
        }
    }
    if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
        xmlhttp = new XMLHttpRequest();
        }
        return xmlhttp;
    } 

    var xhr = getXmlHttp();
    //var xhr = new XMLHttpRequest();
    xhr.open("POST", '//server', true);
    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xhr.onreadystatechange = function() {
    if(xhr.readyState == XMLHttpRequest.DONE && xhr.status == 200) {
        alert('Done');
        }
    }
    xhr.send(dataString);
   });
    
   <?php
   switch ($_SERVER['HTTP_ORIGIN']) {
   case 'http://server': case 'https://server':
   header('Access-Control-Allow-Origin: '.$_SERVER['HTTP_ORIGIN']);
   header('Access-Control-Allow-Methods: GET, PUT, POST, DELETE, OPTIONS');
   header('Access-Control-Max-Age: 1000');
   header('Access-Control-Allow-Headers: Content-Type, Authorization, X-Requested-With');
   break;
   }       
   ?>

Answer 1

the case for new XMLHttpRequest(); seems to be missing in the second function. That is the default class, so most mobile devices would use that