Not able to retrieve $_POST values through ajax call - php

Question

I am having little problem with ajax. Here is my code what I have done so far:
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
getLocation();
});
function getLocation()
{
if (navigator.geolocation)
{
navigator.geolocation.getCurrentPosition(showPosition);
}
else{
alert("Geolocation is not supported by this browser.");
}
}
function showPosition(position)
{
latitude =position.coords.latitude;
longitude= position.coords.longitude;
$.post({ url: 'test.php',
data : ({lat :latitude,long:longitude}),
success: function(data){
alert('done');
}});
}
What I am trying to do is call the function on document ready and trying to retrieve the value of ajax call on the same file where I did call this script. Whenever I reload the page, I don't get any value of :
print_r($_POST['lat']);
I don't know what is the actual problem,I already checked in console and didn't get any error. Please help.

Answer 1

To get the value you need to print it in success callback
$.post({ url: 'test.php',
data : ({lat :latitude,long:longitude}),
success: function(data){
alert(data);
}
});
and if you put
if (isset($_POST['lat']) {
print_r($_POST['lat']);
}
you will get the value in alert box.
EDIT: You can check in php if the reqest came from Ajax using this:
if ($_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest') {
if (isset($_POST['lat']) {
print_r($_POST['lat']);
}
exit();
}
if you put this at the begining you will see only that print_r from ajax call.

Answer 2

The value you are printing is not an array. So you have to print it like,
print $_POST['lat'];
(OR)
echo $_POST['lat'];
AND NOT
print_r($_POST['lat']);
If you want to print all post values mean then you can print it as,
print_r($_POST);

Answer 3

I have solved my problem by own. Here what I have done. I made one more file called test2.php and put my php script over there and call that file in my ajax call. Here the code.
Test.php
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
getLocation();
});
function getLocation()
{
if (navigator.geolocation)
{
navigator.geolocation.getCurrentPosition(showPosition);
}
else{
alert("Geolocation is not supported by this browser.");
}
}
function showPosition(position)
{
latitude =position.coords.latitude;
longitude= position.coords.longitude;
$.ajax({ url: 'test2.php',
data : ({lat :latitude,long:longitude}),
type: 'post',
success: function(data){
if(data=='true'){
window.location = "http://example.com";
}
}
});
}
</script>
Test2.php
//just for example
<?php
echo 'true';
?>
Hope this will help someone in future.