使用PHP将数据发布到不同的域，AJAX不起作用

I'd like to post data from domain1.com to domain2.com using AJAX, but my request fails.

Here's is my code on domain1.com:

$.ajax({
    type: 'POST',
    url: 'https://domain2.com/payment/api/server',
    crossDomain: true,
    data: {
            Name: $("#name").val().trim(), 
            Email: $("#email").val().trim()
          },
    dataType: 'json',
    success: function(data) {
        alert('Success');
    },
    error: function (data) {
        alert('POST failed.');
    }
});

and here's my server side code on domain2.com:

switch ($_SERVER['HTTP_ORIGIN']) {
  case 'http://domain1.com/api/': case 'http://domain1.com/api/':
    header('Access-Control-Allow-Origin: '.$_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;
}

$name = $_POST['Name'];

echo $name; // Just to check if I receive the value from index.php

You are checking if Origin HTTP header equals to 'http://domain1.com/api/'. However, MDN CORS docs say:

The origin is a URI indicating the server from which the request initiated. It does not include any path information, but only the server name.

You have to remove the path from the string, i.e. it has to be 'http://domain1.com'.

Corrected server.php code:

switch ($_SERVER['HTTP_ORIGIN']) {
  case 'http://domain1.com':
    header('Access-Control-Allow-Origin: '.$_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;
}

$name = $_POST['Name'];

echo $name;

As a side note: if you are using the "HTTP_ORIGIN" header to "secure" your requests, you should rethink it. Anyone can spoof this header and arbitrarily set the value. You are better off using some kind of key/secret to avoid unwanted requests. See: Is CORS a secure way to do cross-domain AJAX requests?