Simple Ajax Post to PHP echo - php

Question

I have the following code on product.php .. can't seem to echo post variable from ajax post. Alert displays fine. Please help
JQUERY
document.getElementById("LBTest").onchange = function(){
var lbtest = $('#LBTest :selected').val();
$.ajax({
type: "POST",
url: "product.php",
data: {test: lbtest},
success: function()
{
alert("Successful");
}
});
}
PHP
if(isset($_POST['test'])){
$data = $_POST['test'];
echo $data;
}

Answer 1

You need to do something with the data you receive from the ajax call. For example, to put the result into a <div> called resultDiv:
success: function(data)
{
$('#resultDiv').html(data);
alert("Successful");
}

Answer 2

$.ajax({
type: "POST",
url: "product.php",
data: {test: lbtest},
success: function(data)
{
alert("Successful");
}
});
You need to add the data to the success function that is called. You can do this locally or reference another function meant to handle responses coming back from the server.
success: function(data)
{
console.log(data);
alert(data + " was returned from the server");
}
It is a good idea on the server side to json_encode the objects that are being returned and using error codes that can be more appropriately handled on the client.
handleResponse(data) {
var data = $.parseJSON(data);
if(data.code >= 200 || data.code < 300) {
// modify the dom, add data to a model, take over the world with your web app.
}
}