javascript ajax sorunu

var xhttp = new XMLHttpRequest();

console.log(xhttp);

xhttp.open("GET","alaxgiris.php",true);
//xhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xhttp.send();

xhttp.onreadystatechange=function(){

if (this.readyState == 4 && this.status == 200) {


document.getElementById("sonuc").innerHTML=this.responseText;




}
else{

document.getElementById("sonuc").innerHTML=this.statusText;



}


}

include("config.php");

if (!empty($_POST['email']) && !empty($_POST['password'])) {
    
$giris= $db->prepare("SELECT* FROM uyeler WHERE email=? AND sifre=?");
$giris->bindParam(1,$_POST['email']);
$giris->bindParam(2,$_POST['password']);
$giris->execute();
$gir= $giris->rowCount();
$giro= $giris->fetch(PDO::FETCH_ASSOC);

if ($gir) {

$_SESSION['uye']=1;
$_SESSION['kadi']=$giro['kadi'];
$_SESSION['coin']= $giro['coin'];


}
else{

$_SESSION['uye']=0;


}
if (!$gir) {








?>

<script type="text/javascript">
    
document.getElementById("sonuc").innerHTML="<div class='alert alert-danger' role='alert'>şifreniz veya kullanıcı adınız yanlış lütfen tekrar deneyin..</div>";




</script>



<?php 



}

?>



<?php 
if(@$_SESSION['uye'] == 1){

header("refresh:2; url=anasayfa.php");

echo '<img src="resimana/yuklenme.gif" ';

}



}

var xhttp = new XMLHttpRequest();

console.log(xhttp);

xhttp.open("GET","alaxgiris.php",true);
//xhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xhttp.send();

xhttp.onreadystatechange=function(){

if (this.readyState == 4 && this.status == 200) {


document.getElementById("sonuc").innerHTML=this.responseText;




}
else{

document.getElementById("sonuc").innerHTML=this.statusText;



}


}

<form action="#" method="POST">
    <input type="text" name="username">
    <input type="password" name="password">
    <button type="submit">Gönder</button>
  </form>


  <script>
    const zfc = async (data) => {
      return await new Promise((resolve, reject) => {
        fetch('url', {
          method: 'POST',
          body: data
        }).then(res => res.json())
          .then(res => resolve(res))
          .catch(r=>reject(r))
      })
    }
    var form = document.querySelector('form');
    form.onsubmit =async (e) => {
      e.preventDefault()
      var r = new FormData(form)
      var rt = await zfc(r)
      console.log(rt)
    }
  </script>