How to access javascript variable in php - php

Question

This is my code:
In A Function:
var daaa=document.getElementById('da').value= year+ "-" +month+ "-" +day;
document.form1.bookingsession.focus();
var coords = {
"lat": daaa
};
$.get('bs.php', coords, function () {
alert('data sent');
});
and my php code is:
<?php
$output = isset($_GET['lat']) ? $_GET['lat'] : 0;
print("$output");
?>
And when i print $output i get the value as 0, but actually have to get the value which is on tha variable daaa. Let me know where i made mistake....
Thank you in advance

Answer 1

Try to change
var daaa=document.getElementById('da').value= year+ "-" +month+ "-" +day;
to
var daaa=document.getElementById('da').value + "-" + year+ "-" +month+ "-" +day;
Anyway in such cases yours "number one" action should be check if variable is really set on client side. You can do it through alert(daaa) or console.log(daaa);

Answer 2

change this
var coords = {
"lat": daaa
};
to
var coords = {
lat: daaa
};
you misplaced the double quotes.
http://api.jquery.com/jQuery.get/
example from jquery
//$.get("test.php", { name: "John", time: "2pm" } );

Answer 3

First of all do the action #coramba mentioned,
then modify your javascript code like this:
$.get('bs.php', coords, function (dataThatPhpPrints) {
alert(dataThatPhpPrints);
});
..you will see that it actually returns the value that you have sent to PHP script and PHP scripts returns the print of that.
In order to assure yourself that your scripts prints something modify PHP code to like below:
<?php
$output = isset($_GET['lat']) ? $_GET['lat'] : 0;
print("$output - is response from the PHP!!!");
?>
Now when you run yor javascript, you will get an alert message like
ActualValueOfLATYouSentToPHP - is response from the PHP!!!
Bear in mind, if you want to test your PHP whether it works or not, you cant just simply open it in browser and wait for some magic to happen, as it uses $_GET to get some value meaning you need to provide it as a QueryString with the key being 'lat' :
yourhost/bs.php?lat=someTestValue