Submit -> Execute PHP script -> Alert User -- while staying on same page

Question

I have a page with two submit buttons using if ($_POST['action'] == 'Test SMS') to executed code for my "Test SMS" button. I need to execute code from a PHP script then give an alert box while not leaving the page.

index.html

<form action="updateUserConfig.php" method="post">
<input type='submit' name='action' value='Test SMS' class='btn-test'>
<input type="submit" name="action" value="Save" class="btn btn-primary">
</form>

updateUserConfig.php

if ($_POST['action'] == 'Test SMS') { //action for Test SMS Button

   //grab ntid and phone from header
   if(isset($_POST['ntid'])) $ntid = $_POST['ntid'];
   if(isset($_POST['phone'])) $phone = $_POST['phone'];

   //using the notify_sms_users funtion from send_notification.php
   require 'send_notification.php';
   notify_sms_users(array($ntid), "", 4);

   //alert user that there message has been sent
   $alert = "Your message has been sent to " . $phone;
   echo '<script type="text/javascript">alert("'.$alert.'");';
   echo '</script>';

   header('Location: index.php');

} else {-----action for other submit button------}

I asked a similar question that was marked a duplicate at Alert after executing php script while not leaving current page but was able to come up with a solution so I wanted to share.

Answer 1

I was able to accomplish this by adding a URL query string in my header('location: index.php?text=success) function then using JS I was able to use an if statement to look for the query string and alert if so.

index.html

<form action="updateUserConfig.php" method="post">
    <input type='submit' name='action' value='Test SMS' class='btn-test'>
    <input type="submit" name="action" value="Save" class="btn btn-primary">
</form>

<script type="text/javascript">
$(document).ready(function () {
    if(window.location.href.indexOf("settings=success") > -1) {
       alert("Your settings have been saved");
    }
    else if(window.location.href.indexOf("text=success") > -1) {
       alert("A SMS has been sent!");
    }
});
</script>

updateUserConfig.php

if ($_POST['action'] == 'Test SMS') { //action for Test SMS Button

   //grab ntid and phone from header
   if(isset($_POST['ntid'])) $ntid = $_POST['ntid'];
   if(isset($_POST['phone'])) $phone = $_POST['phone'];

   //using the notify_sms_users funtion from send_notification.php
   require 'send_notification.php';
   notify_sms_users(array($ntid), "", 4);

   header('Location: index.php?text=success');

} else {-----action for other submit button------}
    header('Location: index.php?settings=success');

The only downside to this solution is that I don't have easy access to my PHP $phone variable to tell the user what number the message was sent to.