Selectbox issue - php

Question

I have an issue with my code below. I populated my selectbox from my db which works fine. But when I select an option it wont send the value to my other php file I am relative new to jQuery so I hope that I have a small error in my code I hope that someone can help me.
$(document).ready(function() {
$("#button1").click(function(){
var dropd = $("#drop").val();
$.getJSON('data.php?id='+dropd)
So when I press button1 it should put the value from my selectbox in the variable dropd and send it to the php site data.php right?
So this is the code for my select box which should be alright.
<select id ="drop">
<option disabled selected>--Wähle Station aus--</option>
<?php
$records = mysqli_query($db, "SELECT idStation, Stationname FROM station WHERE fi_idFirma = $id");
while($data = mysqli_fetch_array($records))
{
echo "<option value='".$data['idStation']."'>" .$data['Stationname']."</option>";
}
?>
</select>
My problem is I think that i want several codes to start at once in jquery because when i press button1 it loads the value from dropd to data.php and than it should load an json file where i populate my graphs with.
$(document).ready(function() {
$("#button1").click(function(){
var dropd = $("#drop").val();
$.getJSON('data.php?id='+dropd)
function grab() {
return new Promise((resolve, reject) => {
$.ajax({
url: "data.php",
method: "GET",
success: function(data) {
resolve(data)
},
error: function(error) {
reject(error);
}
})
})
}
grab().then((data) => {
console.log('Recieved our data', data);
let Zeit = [];
let Luft = [];
try {
data.forEach((item) => {
Zeit.push(item.Zeit)
Luft.push(item.Luftfeuchtigkeit)
});
let chartdata1 = {
labels: [...Zeit],
datasets: [{
label: 'Luftfeuchtigkeit',
backgroundColor: 'rgba(200, 200, 200, 0.75)',
borderColor: 'rgba(200, 200, 200, 0.75)',
hoverBackgroundColor: 'rgba(200, 200, 200, 1)',
hoverBorderColor: 'rgba(200, 200, 200, 1)',
data: [...Luft]
}]
};
let ctx = $("#myChart1");
let barGraph = new Chart(ctx, {
type: 'line',
data: chartdata1
});
} catch (error) {
console.log('Error parsing JSON data', error)
}
}).catch((error) => {
console.log(error);
})
I know it looks a bit messy but i hope that you can help me in this case.
This is the data.php file where the select value should arrive.
<?php
header('Content-Type: application/json');
$conn = mysqli_connect("localhost","root","","usera01");
$id = isset($_GET['dropd']) ? $_GET['dropd'] : false;
if ($id) {
echo ($_GET['dropd']);
} else {
$id = 1;
}
$sqlQuery = "SELECT idDatenNr, Luftfeuchtigkeit, Lichtverhältnis, Bodenfeuchtigkeit,Temperatur, Zeit, fi_idStation FROM daten WHERE fi_idStation = '$id'";
$result = mysqli_query($conn,$sqlQuery);
$data = array();
foreach ($result as $row) {
$data[] = $row;
}
mysqli_close($conn);
echo json_encode($data);
?>
Maybe i made here an mistake.