PHP update textbox when value of dropdown is changed - php

Question

I filled my dropdown menu with data from the database. I can select here the name of the product. I have a second textbox on my page. Here i want to show the price of the selected product. I tried different ways but I o net get it working.
First of all this is my dropdown menu where the product name is showed:
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "database";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT * FROM form";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
echo "<select class='form-control select2' id='product1' name='product1' style='width: 100%;'>";
echo "<option selected disabled hidden value=''></option>";
// output data of each row
while($row = $result->fetch_assoc()) {
echo "<option onchange='OnChange()' value='" . $row["id"]. "'>" . $row["name"]. "</option>";
}
echo "</select>";
} else {
echo "0 results";
}
$conn->close();
?>
I want to show the price of the selected value in this textbox:
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "dbsi";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT price FROM form WHERE id='". $product1 ."'";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
echo "<input type='text' class='form-control' name='price1' id='price1' onkeyup='getValues()' value='" . $row["price1"]. "'>";
}
} else {
echo "0 results";
}
$conn->close();
?>
Using this script i only get "0 results" in price1. It doesnt update when i change the selected value of the dropdown menu. How can I ensure that price1 gets updated when i select another value in the dropdown menu?
Update 1:
I tried to add the the following script
<script>
function OnChange(){
UpdatePoints(<?php echo $price1; ?>);
}
echo "<script type='text/javascript'> window.onchange=load; </script>";
</script>
When I use this script i still get "0 results"
Update 2:
The following is still not working:
//filename: test.php
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "database";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT * FROM forms";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
echo "<select class='form-control select2' id='product1' name='product1' onChange='getstate(this.value);' style='width: 100%;'>";
echo "<option selected disabled hidden value=''></option>";
// output data of each row
while($row = $result->fetch_assoc()) {
echo "<option value='" . $row["id"]. "'>" . $row["name"]. "</option>";
}
echo "</select>";
} else {
echo "0 results";
}
$conn->close();
?>
<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "database";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT * FROM forms WHERE id='". $product1 ."'";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
while($row = $result->fetch_assoc()) {
echo "<div id='price-list'>";
echo "<input type='text' class='form-control' name='price1' id='price1' value='" . $row["price"]. "'>";
echo "</div>";
}
} else {
echo "0 results";
}
$conn->close();
?>
<script>
function getprice(val) {
$.ajax({
type: "POST",
url: "test.php",
data:'id='+val,
success: function(data){
$("#price-list").html(data);
}
});
}
</script>
<?php
$product1=$_POST['price1'];
?>

Answer 1

make a ajax call and get the value of using post
<script>
function getprice(val) {
$.ajax({
type: "POST",
url: "index.php",
data:'priceid='+val,
success: function(data){
$("#price-list").html(data);
}
});
}
</script>
<select class='form-control select2' id='product1' name='product1' style='width: 100%;' onChange="getstate(this.value);">
//yourcode
</select>
<div id="price-list">
</div>
index.php
<?php
$product1=$_POST['priceid'];
?>