How to use a div id as a php var - php

Question

I have the following function that pass to the div with id = "window", the value dbdata from the database.
$(document).ready(function() {
setInterval(function () {
$('#window').load('crt.php');
)};
)};
How can I get the id value and use it in the php code below?
without refresh the page?
if ($id = $row["dbdata"]) { do something }
I added the rest of the code:
index.html
`<div id = "window"></div>`
`if ($id = $row["dbdata"]) {do something}`
`<script type="text/javascript">
$(document).ready(function() {
setInterval(function () {
$('#window').load('crt.php')
}, 3000);
});
</script>`
crt.php
`<?php
$conn = new mysqli('localhost', 'root', '', 'user');
if ($conn->connect_error) {
die("Connection error: " . $conn->connect_error);
}
$result = $conn->query("SELECT id FROM data");
if ($result->num_rows > 0) {
while ($row = $result->fetch_assoc()) {
echo $row['dbdata'] . '<br>';
}
}
?>`
Thank you in advance.

Answer 1

You can pass values in URL parameters.:
$('#window').load('crt.php?id=window')
Then in your php code you can retrieve the parameter using:
$id = $_GET["id"];

Answer 2

a simple way could be assign the GET param in your jquery load url and use it in your php code
$(document).ready(function() {
setInterval(function () {
$('#window').load('crt.php?id=window')
.
if ($_GET['id'] = $row["dbdata"]) { do something }
or you instead of load could use ajax get eg :
$.get( "crt.php?id=window", function( data ) {
alert( "Data Loaded: " + data );
});
in your crt.php
if ($_GET['id'] = $row["dbdata"]) {
return "hello!";
}