POST php headers failing

POST php headers failing

When I call a script from Javascript
var user = document.getElementById('username').value;
var pass = document.getElementById('password').value;
var conf = document.getElementById('confirm').value;
var code = document.getElementById('code').value;
if(code.length == 0 || pass.length == 0 || user.length == 0 ||
conf.length == 0) {
alert("Entries empty");
} else if(pass != conf) {
alert("Passwords don't match");
}
window.location =
"scripts/changepassword.php?Username="+user+"&Password="+pass+"&Code="+code;
changepassword.php in my scripts folder has the following headings its
refreshing the current page and not passing the parameters into the
script. any ideas?
it gives me error2.
scripts/changepassword.php
if (isset($_GET['Username']) && isset($_GET['Password'])&&
isset($_GET['Code'])) { ... } else {
$response = array('result'=>"error2");
echo json_encode($response);
echo "hi";
}