Check Username Availability with Vue.js and PHP

Live username availability checking on the registration page is the common feature in most of the website.

This will notify the user whether the username is already been taken or not before submitting.

To do this require AJAX.

Send a request to check the username on the bases of response perform the action.

In this tutorial, I show how you can check username availability using Vue.js and PHP.

1. Table structure

I am using users table in the example.

CREATE TABLE `users` ( 
   `id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT, 
   `username` varchar(80) NOT NULL, 
   `name` varchar(80) NOT NULL, 
   `password` varchar(80) NOT NULL 
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

2. Configuration

Create a new config.php file.

Completed Code

<?php 
$host = "localhost"; /* Host name */ 
$user = "root"; /* User */ 
$password = ""; /* Password */ 
$dbname = "tutorial"; /* Database name */ 
// Create connection 
$con = mysqli_connect($host, $user, $password,$dbname); 
// Check connection 
if (!$con) { 
  die("Connection failed: " . mysqli_connect_error()); 
}

3. HTML

Create a textbox and <span> to show message.

In the textbox added v-model='username' and @keyup='checkUsername()'.

To display the message in <span> added {{responseMessage}} and v-bind:class to change class according to isAvailable value.

Completed Code

<style > 
.available{ 
  color: green; 
} 
.notavailable{ 
  color: red; 
} 
</style> 
<div id='myapp'> 
   Enter username : <input type='text' v-model='username' @keyup='checkUsername()'> 
   <span v-bind:class="[isAvailable ? 'notavailable' : 'available']" >{{responseMessage}}</span> 
</div>

4. PHP

Create a ajaxfile.php file.

Check username in the users table. If record found then assign 1 to $found.

Return $found.

Completed Code

<?php 
include "config.php"; 
$username = ""; 
$found = 0;
 
if(isset($_GET['username'])){ 
  $username = mysqli_escape_string($con,$_GET['username']); 
  // Check username 
  $result = mysqli_query($con,"select * from users WHERE username='".$username."'"); 
  
  if(mysqli_num_rows($result) > 0){ 
    $found = 1; 
  } 
} 
echo $found;

5. Script

Create 3 data variable — username, isAvaialble, and responseMessage.

Here, isAvailable is used to toggle <span> class and the responseMessage to display a message.

Define a checkUsername method.

Send GET request where pass username: username. On successful callback assign app.isAvailable = response.data.

If response.data == 0 then assign app.responseMessage = "Username is Available." otherwise app.responseMessage = "Username is not Available.".

Completed Code

var app = new Vue({ 
  el: '#myapp', 
  data: { 
    username: '', 
    isAvailable: 0, 
    responseMessage: '' 
  }, 
  methods: { 
    checkUsername: function(){ 
      var username = this.username.trim(); 
      if(username != ''){ 
        axios.get('ajaxfile.php', { 
           params: { 
             username: username 
           } 
        }).then(function (response) { 
           app.isAvailable = response.data; 
           if(response.data == 0){ 
             app.responseMessage = "Username is Available."; 
           }else{ 
             app.responseMessage = "Username is not Available."; 
           } 
        }).catch(function (error) { 
           console.log(error); 
        }); 
      }else{ 
         this.responseMessage = ""; 
      } 
     } 
  } 
})

6. Conclusion

It is better to prevent the user from selecting existing username before submitting the form.

Also, check the username availability while inserting the record.

You can view working demo of tutorial example here.

Originally published at makitweb.com on April 16, 2018.