We have a small html code:

& lt; input type = "file" multiple = "multiple" accept = "image / *" & gt;
& lt; a href = "#" class = "submit button" & gt; Upload files & lt; / a & gt;

I send collected images for processing via ajax

let files;
$ ('input [type = file]'). change (function () {
  files = this.files;
  if (files.length == 8) {
    $ ('. erroResponse'). hide ();
  } else {
    $ ('. erroResponse'). show ();
  }
});
$ ('. submit.button'). click (function (event) {
  event.stopPropagation (); // Stop what is happening
  event.preventDefault (); // Completely stop what is happening
  // Supply the form data and add the file data from files to it
  var data = new FormData ();
  $ .each (files, function (key, value) {
    data.append (key, value);
  });
  // Send the request
  $ .ajax ({
    url: '/acces/default/loadimage.php',
    type: 'POST',
    data: data,
    cache: false,
    contentType: false,
    processData: false,
    dataType: "json",
    success: function (respond, textStatus, jqXHR) {
      if (typeof respond.error === 'undefined') {
        // Files uploaded successfully, do something here
        str = respond.replace (/ \] \ [/ g, ",");
        var data = JSON.parse (str);
        console.log (data);
      }
      else {
        console.log ('server RESPONSE ERRORS:' + respond.error);
      }
    },
    error: function (jqXHR, textStatus, errorThrown) {
      console.log ('AJAX request ERRORS:' + textStatus);
    }
  });
});

As a result, I get an error: parsererror;
dataType: change to jsonp – same error;
dataType: change to text and get another error –

SyntaxError: JSON.parse: unexpected end of data at line 1 column 1 of the JSON data

Answer 1, authority 100%

Remove the line

dataType: "json",

or replace it with

dataType: "text",

Your response from the server does not match the JSON format.