XMLHttpRequest to PHP script - what's missing here? - php

Question

This is my first time using AJAX, and I'm trying to send JS variables to a PHP script. I've got an XMLHttpRequest but it doesn't seem complete - what am I missing?
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(successFunction, errorFunction);
}
else {
document.write("Geolocation is required for this page.");
}
function successFunction(position) {
var lat = position.coords.latitude;
var lng = position.coords.longitude;
// document.write("<a href='http://api.geonames.org/findNearbyPlaceNameJSON?lat="+lat+"&lng="+lng+"&username=sebastiano'>my town</a>");
var xmlhttp;
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else {
// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","location.php?lat=position.coords.latitude",true);
xmlhttp.send();
// SOMETHING MISSING HERE?
}
function errorFunction(position) {
document.write("Error");
}

Answer 1

It appears that you're not passing the contents of your variable to the open command.
xmlhttp.open("GET","location.php?lat=position.coords.latitude",true);
in this example your lat will contain a string with contents "position.coords.latitude"
instead try
xmlhttp.open("GET","location.php?lat="+position.coords.latitude,true);
Or better yet, use the variables you created at the top of the function and pass both long and lat in.
xmlhttp.open("GET","location.php?lat=" + lat + "&long=" + lng,true);

Answer 2

you are sending it with "position.coords.latitude" as value...
try xmlhttp.open("GET","location.php?lat=" + position.coords.latitude,true);
Also, take a look at jQuery

Answer 3

Try this:
var xmlhttp;
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else {
// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState==4 && xmlhttp.status==200){
console.log(xmlhttp.responseText);
}
}
xmlhttp.open("GET","location.php?lat=" + position.coords.latitude,true);
xmlhttp.send();