Live Username Availability Check using PHP and jQuery AJAX

This post about Twitter used jQuery plug-in JavaScript code in registration page  username Availability check and update Screen name.

This is very useful stuff, this is the best way to implement it and the only thing you have to modify just some database connection parameters.


Step1: Modifiy dbconnection.php

Change MySQL connection parameters in dbconnection.php
<?php
$mysql_hostname = "Host name";
$mysql_user = "UserName";
$mysql_password = "Password";
$mysql_database = "Database Name";
$prefix = "";
$bd = mysql_connect($mysql_hostname, $mysql_user, $mysql_password) or die("Could not connect database");
mysql_select_db($mysql_database, $bd) or die("Could not select database");
?>

Step2: cofigure check.php

Change table name and column name in SQL query.

<?php
// This is a code to check the username from a mysql database table

if(isSet($_POST['username']))
{
$username = $_POST['username'];

include("dbconnection.php");

$sql_check = mysql_query("SELECT user FROM {$prefix}users WHERE user='$username'");

if(mysql_num_rows($sql_check))
{
echo '<span style="color: red;">The username <b>'.$username.'</b> is already in use.</span>';
}
else
{
echo 'OK';
}}
?>

Step 3. Add JQuery framework on your page

First, you have to download the jQuery plugin and add a link to the framework within the tag <head> of the page:

Step 4. Registration.php Code

HTML code for this example is very simple:

<script src="js/jquery.jstype="text/javascript">/script>
<script type="text/javascript">
pic1 = new Image(16, 16); 
pic1.src = "loader.gif";

$(document).ready(function(){

$("#username").change(function() { 

var usr = $("#username").val();

if(usr.length >= 3)
{
$("#status").html('<img align="absmiddle" src="loader.gif" /> Checking availability...');

$.ajax({ 
type: "POST"
url: "check.php"
data: "username="+ usr, 
success: function(msg){ 

$("#status").ajaxComplete(function(event, request, settings){ 

if(msg == 'OK')

$("#username").removeClass('object_error'); // if necessary
$("#username").addClass("object_ok");
$(this).html(' <img align="absmiddle" src="accepted.png" /> ');

else 

$("#username").removeClass('object_ok'); // if necessary
$("#username").addClass("object_error");
$(this).html(msg);
}});}});}
else
{
$("#status").html('The username should have at least 3 characters.');
$("#username").removeClass('object_ok'); // if necessary
$("#username").addClass("object_error");
}});});

//-->

</script>


<div>
<label>User name:</label>
<input type="text" id="username" name="username" class="inn"/> 
</div>
<div id="status"></div>


Update Screen Name 
settings.js : enables jQuery functionalities 
javascript code enables the jQuery functionalities.
var twitter=function()
{
var rtn={updateUrl:function(value){$("#username_url").html(value)},
screenNameKeyUp:function(){
jQuery("#user_screen_name").keyup(function(event){var screen_name=jQuery("#user_screen_name");

}

)
},return rtn}();

Copy jquery.js and settings.js in js folder

Registration.php Final code
<html>
<head>
<script src="js/jquery.jstype="text/javascript">/script>
<script src="js/settings.jstype="text/javascript"></script> 
<script type="text/javascript">
pic1 = new Image(16, 16); 
pic1.src = "loader.gif";

$(document).ready(function(){

$("#username").change(function() { 

var usr = $("#username").val();

if(usr.length >= 3)
{
$("#status").html('<img align="absmiddle" src="loader.gif" /> Checking availability...');

$.ajax({ 
type: "POST"
url: "check.php"
data: "username="+ usr, 
success: function(msg){ 

$("#status").ajaxComplete(function(event, request, settings){ 

if(msg == 'OK')

$("#username").removeClass('object_error'); // if necessary
$("#username").addClass("object_ok");
$(this).html(' <img align="absmiddle" src="accepted.png" /> ');

else 

$("#username").removeClass('object_ok'); // if necessary
$("#username").addClass("object_error");
$(this).html(msg);
}});}});}
else
{
$("#status").html('The username should have at least 3 characters.');
$("#username").removeClass('object_ok'); // if necessary
$("#username").addClass("object_error");
}});});

//-->

</script>
</head>
<body>
<div>

<label>User name:</label>
<input type="text" id="username" name="username"onkeyup="Twitter.updateUrl(this.value)" class="inn"/> 

http://xyz.com/<span id="username_url" class="url">USERNAME</span> 

</div>
<div id="status"></div>
<script type="text/javascript">
$( function () {
twitter.screenNameKeyUp();
$('#user_screen_name').focus();
});

</script>
</body>
</html>


In this tutorial, we will see a PHP script to implement username live check feature using AJAX, jQuery, and MySQL. This is a common and popular feature in most of the websites available online.

While creating a user account, just after the user enters the username, an AJAX call will request the PHP page at the server side to get the availability status of the username. The PHP page matches the user input against the database and returns the response text based on the availability.

Check Username Availability Form Interface
This form contains username input field and triggers AJAX call on blur event of this input. The loader icon is shown to the user until the availability status is returned to the user interface.

<div id="frmCheckUsername">
<label>Check Username:</label>
<input name="username" type="text" id="username" class="demoInputBox" onBlur="checkAvailability()"><span id="user-availability-status"></span>
</div>
<p><img src="LoaderIcon.gif" id="loaderIcon" style="display:none" /></p>

jQuery AJAX Handler to Request User Availability

This Javascript function uses jQuery.ajax to send the username entered by the user along with the request for a PHP page.

function checkAvailability() {
$
("#loaderIcon").show();
jQuery
.ajax({
url
: "check_availability.php",
data
:'username='+$("#username").val(),
type
: "POST",
success
:function(data){
$
("#user-availability-status").html(data);
$
("#loaderIcon").hide();
},
error
:function (){}
});
}

Match Username against Database using PHP

This PHP script is executed as a result of the jQuery AJAX call. It compares database and user data to check username. Based on the availability status it will respond to the AJAX call.
require_once("dbcontroller.php");
$db_handle
= new DBController();
if(!empty($_POST["username"])) {
$result
= mysql_query("SELECT count(*) FROM users WHERE userName='" . $_POST["username"] . "'");
$row
= mysql_fetch_row($result);
$user_count
= $row[0];
if($user_count>0) echo "<span class='status-not-available'> Username Not Available.</span>";
else echo "<span class='status-available'> Username Available.</span>";
}
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