AJAX PHP

<p>Start typing a name in the input field below:</p>
<p>Suggestions: <span id="txtHint"></span></p>

<form>
First name: <input type="text" onkeyup="showHint(this.value)">
</form>

<script>
function showHint(str) {
  if (str.length == 0) {
    document.getElementById("txtHint").innerHTML = "";
    return;
  } else {
    const xmlhttp = new XMLHttpRequest();
    xmlhttp.onload = function() {
      document.getElementById("txtHint").innerHTML = this.responseText;
    }
  xmlhttp.open("GET", "/files/gethint.php?q=" + str);
  xmlhttp.send();
  }
}
</script>

<?php
/* Array with names */
$a[] = "Ahmed";
$a[] = "Ali";
$a[] = "Adel";
$a[] = "Mohamed";
$a[] = "Maged";
$a[] = "Mahmoud";
$a[] = "Marawan";
$a[] = "Moustaf";
$a[] = "Nader";
$a[] = "Noah";
$a[] = "Nasir";
$a[] = "Nour";
$a[] = "Nadia";
$a[] = "badr";
$a[] = "Bilal";
$a[] = "Youssef";
$a[] = "Younes";
$a[] = "Hussein";
$a[] = "Hoda";
$a[] = "Hamza";
$a[] = "Hadeel";
$a[] = "Seham";
$a[] = "saleh";
$a[] = "salah";
$a[] = "samar";
$a[] = "Liza";
$a[] = "Elizabeth";
$a[] = "Ellen";
$a[] = "Wenche";
$a[] = "Vicky";

/* get the q parameter from URL */
$q = $_REQUEST["q"];

$hint = "";

/* lookup all hints from array if $q is different from "" */
if ($q !== "") {
  $q = strtolower($q);
  $len=strlen($q);
  foreach($a as $name) {
    if (stristr($q, substr($name, 0, $len))) {
      if ($hint === "") {
        $hint = $name;
      } else {
        $hint .= ", $name";
      }
    }
  }
}

/* Output "no suggestion" if no hint was found or output correct values */
echo $hint === "" ? "no suggestion" : $hint;
?>