b

b.php

<?php 

function validation(){
    $dbServer = 'localhost';
    $dbUserName = 'root';
    $dbPassword = '';
    $dbName = 'DBeoi';

    if (isset($_POST['eoinumber'],$_POST['lastcheck'])){
        $eoinumber = $_POST['eoinumber'];
        $lastname = $_POST['lastcheck'];

        $dbConx = new mysqli($dbServer, $dbUserName, $dbPassword, $dbName);
        $eoinumber = $dbConx->real_escape_string($eoinumber);
        $lastname = $dbConx->real_escape_string($lastname);

        if (!$dbConx){
            echo '<p>Unable to connection to database. </p>';
        } else {
            $sql = "SELECT id FROM eoi WHERE id='$eoinumber'";
            $query = $dbConx->query($sql);
            if ($query->num_rows){
                echo 'exists';
            } else {
                echo 'ok';
            }
        }

    }



}
?>