AJAX with Database

In this video I am giving more explanations to the examples from w3schools.
These examples combine all main parts that you've learned in the course in some real life examples using XML and SQL database on the server side working together with HTML, JavaScript and AJAX on the server side.

Note that in my example I added the check of the parameter passed from AJAX to the PHP file:

<?php
$q=$_GET['q'];
// check what has been passed as "q"
echo "parameter". $q;

So if you have a message "parameter " and nothing in it - this means that the q parameter was not passed to the PHP file. Please check the whole chain of getting the value into q and properly passing it to php.

For debugging purposes, you can test your PHP files separately to see if your table and the KEY search field work in the SELECT statement. For this just start your PHP file, where you can comment $q out:

// $q=$_GET['q'];

And after that your SELECT statement  formed with WHERE clause and directly inserted field value should return a record corresponding to that value. Just use your own table name after the connection to your database works correctly:

$sql="SELECT * FROM user WHERE id = 'your key/unique field name'";

If  $result = mysqli_query($con,$sql); will not return anything  - you can check the same SELECT command manually from the SQL section of phpMyAdmin interface to see if the database, table, and key field names where spelled properly.