jQuery Ajax无法正常工作

This is my function to call ajax:

var sendAjax = function(type, data, callback) {
  $.ajax({
    url: homepage + 'server_ajax.php',
    type: 'POST',
    data: {
      type: type,
      data: JSON.stringify(data)
    }
  }).done(function(data) {
    console.log(data);
    callback(true, JSON.parse(data));
  }).fail(function() {
    console.log('NO');
    callback(false, {});
  });
};

1. Variable homepage contains valid URL. It is same domain, so this is not the problem.

2. My server_ajax.php has only this: echo "awdawda wawddawawd"; - nothing more (testing purposes).

3. I tried to put breakpoints to $.ajax... and to the console logs. First breakpoint works, but functions done and fail never run.

4. No error show up in the browser console

5. My jQuery is include (I'm sure), I use require.js and everything else in this JS file using jQuery works well.

6. I also tried change URL to something invalid (like server_ajax2.php) and console prints error 404 - like it would.

7. Also tried with dataType: 'json' or removing data object...

Any ideas, what should I try? I also tried some answers on this site (don'r flag this as duplicate, I tried like everything), but nothing helped me.

Have you tried doing the following on the server_ajax.php file:

echo json_encode('awdawda wawddawawd');
header('X-PHP-Response-Code: 200', true, 200);

This encodes the response as JSON so that your JavaScript code can read the content, and gives the standard success header (200 OK) to the page so that the $.ajax code knows the query was successful.

Here try this, since your getting data back perhaps its your success failure functions.

$.ajax({
  url: homepage + 'server_ajax.php',
  type: 'POST',
  dataType : 'json',
  contentType: 'text/plain',
  data: {
    type: type,
    data: JSON.stringify(data)
  },
  success: function(data) {
    console.log(data);
    callback(true, JSON.parse(data));
   },
   error: function() {
     console.log('NO');
     callback(false, {});
   }
});