Show loading image while PHP is executing

Question

I would like to show loading image while the php script is executing. I have read different answers on how to do that but most of them stated that I should have a separate php page. However I am using single page to show the rows, so how can I be able to show loading image?

Example of select query, I am using to fetch the data:

 $stmt = $mydb->prepare("select * from table where firstname = ?  and id = ? ");
 $stmt->bind_param('ss', $firstname, $id);
 $stmt->execute();
 $stmt->close();

Answer 1

In the majority of cases, you would have two pages. The first page, client-side, makes a call to another page, server-side, and shows a pretty spinning thing while it waits. When the server-side page finishes loading (when your query completes) your first page receives a response and then you can hide the pretty spinning thing to let your user know it's finished.

You can use AJAX - in pure Javascript or a lot simpler in jQuery - to dynamically load some data from your PHP page and show a spinning thingy while it waits. I've used jQuery here.

CSS

#loading_spinner { display:none; }

HTML

<img id="loading_spinner" src="loading-spinner.gif">

<div class="my_update_panel"></div>

jQuery

$('#loading_spinner').show();

var post_data = "my_variable="+my_variable;
$.ajax({
    url: 'ajax/my_php_page.php',
    type: 'POST',
    data: post_data,
    dataType: 'html',
    success: function(data) {
        $('.my_update_panel').html(data);
//Moved the hide event so it waits to run until the prior event completes
//It hide the spinner immediately, without waiting, until I moved it here
        $('#loading_spinner').hide();
    },
    error: function() {
        alert("Something went wrong!");
    }
});

PHP (my_php_page.php)

<?php
// if this page was not called by AJAX, die
if (!$_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest') die('Invalid request');

// get variable sent from client-side page
$my_variable = isset($_POST['my_variable']) ? strip_tags($_POST['my_variable']) :null;

//run some queries, printing some kind of result
$SQL = "SELECT * FROM myTable";
// echo results
?>

Answer 2

You can't really do this in PHP itself, you'd have to do something in JavaScript for that. So what you would probably want to do is have JQuery show a loading spinner, then execute an AJAX request to your PHP job, and when you get data back, hide the loading indicator.