Amardeep Thadisetty
Amardeep Thadisetty
1,347 Points

how to display alert box in login screen in php if a user enter's a wrong password. I have tried that in ajax. Is there

Is there any way to do it. when a user enter's a corret username and password we let him in. IF he don't how to achieve it?

3 Answers

Jeremy Hayden
Jeremy Hayden
1,740 Points

Php is server side script, meaning its done once the website hits the users browser.

Pop up windows are usually done with a client side script like javascript.

You can either code the javascript directly into your html, or make it dynamic by echoing it out of php. But php is not making the pop up, javascript is.

Hi Amardeep,

Here is a simple example:


* Query database to retrieve stored 
* username and password then check validity below

$Query_username = "something1";
$Query_pswd = "something2";

$userName = $_POST['userName'];
$pswd = $_POST['pswd'];

if(($userName == $Query_username) && ($pswd == $Query_pswd)) {

  echo "OK, logged in, good to go.";
} else {
  $message = "Username and/or Password incorrect.\\nTry again.";
  echo "<script type='text/javascript'>alert('$message');</script>";



Justin Black
Justin Black
24,266 Points

to do it in javascript, you'd want to submit the entire form using javascript....

<script type="text/javascript">
$(document).on('click', '.formsubmitbutton', function(e) {
        type: "POST",
        url: $(".form").attr('action'),
        data: $(".form").serialize(),
        success: function(response) {
             if (response === "success") {
             } else {
                   alert("invalid username/password.  Please try again");

Now that is a very basic example, but would function.. The PHP is pretty simple... check database, to see if the username and password exist and match... if not echo "error"; if they do echo "success"