JSFiddle - React, Tailwind, and code Playground

JavaScript

<script>
function showUser(str)
{
if (str=="")
  {
  document.getElementById("txtHint").innerHTML="";
  return;
  } 
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
    }
  }
xmlhttp.open("GET","getuser.php?q="+str,true);
xmlhttp.send();
}
</script>
<?
// Load Joomla! configuration file
require_once('configuration.php');
// Create a JConfig object
$config = new JConfig();
// Get the required codes from the configuration file
$server	= $config->host;
$username	= $config->user;
$password	= $config->password;
$database = $config->db;
// Tools dropdown
$con = mysql_connect($server,$username,$password);
mysql_select_db($database);
$sql = "SELECT cb_dealerid FROM cypg8_comprofiler";
$result = mysql_query($sql);
?>
<form>
<?
	echo "<select name='cb_dealerid' onchange='showUser(this.value)'>";
	while ($row = mysql_fetch_array($result)) {
    echo "<option value='" . $row['cb_dealerid'] . "'>" . $row['cb_dealerid'] . "</option>";
		}
	echo "</select>";
	?>
</form>
<br>
<div id="txtHint"><b>Person info will be listed here.</b></div>