Javascript + Load AJAX function on page load + Pass Javascript vars to PHP - php

Question

I have again a little problem with a javascript (i am a real noob regardin that). This time I would like to load an AJAX function on page load in order to save some javascript variables to php sessions. I figured out thats the best way to pass javascript vars to php. If there is a better way (besides cookies), dont hesitate to let me know :)
For now I would like to:
-pass javascript variables to an external php page on page load
-save variables in php
-use the php variables without pagereload
Here is my script so far:
$(document).ready(function () {
function save_visitor_details() {
$(function() {
var visitor_country = geoip_country_name();
var visitor_region = geoip_region_name();
var visitor_lat = geoip_latitude();
var visitor_lon = geoip_longitude();
var visitor_city = geoip_city();
var visitor_zip = geoip_postal_code();
var dataString = 'visitor_country='+ visitor_country +'&visitor_region='+ visitor_region +'&visitor_lat='+ visitor_lat +'&visitor_lon='+ visitor_lon +'&visitor_city='+ visitor_city +'&visitor_zip='+ visitor_zip;
$.ajax({
type: "POST",
url: "inc/visitor_details.php",
data: dataString,
success: function(res) {
alert ("saved");
//$('#result').html(res);<-- should contain variables from inc/visitor_details.php
});
}
});
return false;
}
});
Thanks in advance!
Edit: I changed it a little and got it to work by adding the javascript variables into a hidden form, submit the form with the ajax script above and save variables into php session array at the backend php file.Thanks any1 for your time!!!

Answer 1

I don't really understand what is the question here. But here are a few advices.
rather than serializing the data yourself, you should rather let jQuery do that for you:
$.post('inc/visitor_details.php', {country: geoip_country_name() /* stuff */}, function(data) {
alert('ok!'); alert(data);
});
be aware that, by passing data to your server using Javascript, users can send whatever data they want, including fake data. So handle it with care.
Then entire process may looks like this:
/* javascript */
$(document).ready(function() {
function save_visitor_details() {
$.post('inc/visitor_details.php', {
country: geoip_country_name(),
region: geoip_region_name(),
lat: geoip_latitude(),
lon: geoip_longitude(),
city: geoip_city(),
zip: geoip_postal_code()
}, function(data) {
/* do whatever you want here */
alert(data);
}, 'json');
}
save_visitor_details();
});
/* PHP */
<?php
$keys = array('country', 'region', 'lat', 'lon', 'city', 'zip');
$output = array();
foreach($keys as $key) {
do_some_stuff($_POST[$key]);
$output[$key] = $_POST[$key];
}
header('Content-type: text/plain; charset=utf-8');
echo json_encode($output);
?>

Answer 2

JavaScript:
var http = createRequestObject() ;
function createRequestObject(){
var obj;
var browser = navigator.appName;
if(browser == "Microsoft Internet Explorer"){
obj = new ActiveXObject("Microsoft.XMLHTTP");
}else{
obj = new XMLHttpRequest();
}
return obj;
}
function sendReq(str){
http.open('get', str);
http.onreadystatechange = handleResponse;
http.send(null);
}
sendReq("someurl?var=yourvar");
Php:
$var = $_GET['var']; // use some security here.