ajax: weird “boundary” and “content-disposition” names on post sent (no jquery!)

i know how to send post forms and process it server side with php… something like

<!-- html form -->

<form action='getform.php' method='post'>
 your first name: <input name='fName'/>
 your last name : <input name='lName'/>
 <input type='submit'/>
</form>

//--- getform.php ---

print_r($_POST);
// prints something like:
// Array(
    ["fName"]=>["John"],
    ["lName"]=>["Doe"]
// );

echo "your full name is: {$_POST['fName']} {$_POST['lName']}";
// prints something like "your full name is: John Doe"

i am just developing it on my php server… the actual form has many more inputs and later i have to flash into an embedded system, so to make it more efficient (memory usage, responsiveness, etc) i decided to do it with AJAX…

to simplify things, i read that you can create a FormData directly from <form> and pass it directly to send() method, something like

<!-- html form -->

<form onsubmit='ajaxPost(this);return false;'>
 your first name: <input name='fName'/>
 your last name : <input name='lName'/>
 <input type='submit'/>
</form>

<script>
 function getResponse(ans){
  alert('your full name is: ' + ans);
 }

function ajaxPost(myForm){
 var xhr = new XMLHttpRequest();
 xhr.onload = function(){getResponse(this.responseText);};
 xhr.open('POST', 'getform.php');
 xhr.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
 xhr.send(new FormData(myForm));
}
</script>

//--- getform.php ---
echo $_POST['fName'].' '.$_POST['lName'];

however the form data i recieve with php is something with weird format like

// print_r($_POST);
Array(
    [------WebKitFormBoundaryDP16ROTp3RJIUWFf
Content-Disposition:_form-data;_name] => "fName"

John
------WebKitFormBoundaryDP16ROTp3RJIUWFf
Content-Disposition: form-data; name="lName"

Doe
------WebKitFormBoundaryDP16ROTp3RJIUWFf--

);

it seems like php uses parse_str() function internally to convert received request from querystring format to store in $_POST array, but as the request seem chunked instead it fails, i tried by changing Content-Type in XHR and <form> but nothing changes

the question: using just ajax and plain javascript, how can i get rid all of those ‘boundaries’ and ‘disposition’ chunked things and send a normal querystring format POST, parsed by php like a normal array like [“fName”=>”John”, “lName”=>”Doe”] ???

… i had searched some help or documentation on internet but i hadn’t found anything about this 🙁 … thanks in advance

Answer

@atesin: i am yourself from the future, bringing you the answer you searched for

you can use URLSearchParams() before to transform FormData into urlencoded format, this way

xhr.send(new URLSearchParams(new FormData(myForm)));

this answer was taken from here: FormData change from multipart/form-data to form-urlencoded?