connect.php

<!--Build the HTML -->
<form action="index.php" method="post">
  <input type="text" name="dbname">
  <input type="submit" value="Submit">
</form>
<!--Use JS to prevent form resubmission on refresh/back button -->
<script>
    if ( window.history.replaceState ) {
        window.history.replaceState( null, null, window.location.href );
    }
</script>
<?php
//Set up our variables
$servername = "localhost";
$dbname = $_POST["dbname"]; //pull the value from the form
$username = "utrial";
$password = "utrial1";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
   die("<p>Connection failed: " . "<span class=\"error\">" . $conn->connect_error . "</span></p>");
}
echo "<p>You're currently connected to the database named: <span class=\"success\">$dbname</span></p>";
?>