Ajax PhoneGap always error - php

Question

I must make an application, and I've decided to use PhoneGap, but my Ajax always say "ERROR", and I don't know why, because the insert works very well...
$("#test").click(function() {
var name = $("#name").val();
var password = $("#password").val();
alert(name+' '+password);
$.ajax({
type: "POST",
url: "http://191.165.1.16/PULZ/ajax_action.php",
// contentType: "application/json; charset=utf-8",
dataType: "json",
data : {
actionname : 'insert',
name:name,
password:password
},
success: function(data) {
alert("work");
},
error: function(data) {
alert("There was an error loading the feed");
}
});
});
And my PHP code
if (isset($_POST["actionname"]) && !empty($_POST['actionname'])){
$actionname = $_POST['actionname'];
if($actionname == 'insert'){
$connect = new PDOsql();
$name = $_POST['name'];
$password = md5($_POST['password']);
$sql="INSERT INTO user(name,password) VALUES(?,?)";
$opt = array($name, $password);
$connect->query($sql,$opt);
$connect = null;
die(
json_encode(
array(
'state'=>'success'
)
)
);
}
}

Answer 1

Try this
JAVASCRIPT
$("#test").click(function() {
var name = $("#name").val();
var password = $("#password").val();
alert(name + ' ' + password);
$.ajax({
type: "POST",
url: "http://191.165.1.16/PULZ/ajax_action.php",
// contentType: "application/json; charset=utf-8",
dataType: "json",
data: {
actionname: 'insert',
name: name,
password: password
},
headers: {
'Content-Type': 'application/json'
}
success: function(data) {
alert("work");
},
error: function(data) {
alert("There was an error loading the feed");
}
});
});
PHP
if (isset($_POST["actionname"]) && isset($_POST['name']) && isset($_POST['password'])){
$actionname = $_POST['actionname'];
$name = $_POST['name'];
$password = $_POST['password'];
if($actionname == 'insert'){
$connect = new PDOsql();
$name = $_POST['name'];
$password = md5($_POST['password']);
$sql="INSERT INTO user(name,password) VALUES($name,$password)";
$opt = array($name, $password);
$connect->query($sql,$opt);
$connect = null;
die(
json_encode(
array(
'state'=>'success'
)
)
);
}
}

Answer 2

You can't use "empty()" with a non variable element, you will receive a internal server error "500", always.
Note: Prior to PHP 5.5, empty() only supports variables; anything else
will result in a parse error. In other words, the following will not
work: empty(trim($name)). Instead, use trim($name) == false.
PHP Manual - empty