AJAX and form validation using AJAX - ajax

Question

I have been trying to submit a form using ajax. I can already read the errors when there is one but I can't get the message when there is no error. Please find below my php code and then the jquery codes as follows.
script side code
$error=[];
$message=[];
$name=isset($_POST["name"])?$_POST["name"]:"";
$email=isset($_POST["email"])?$database->cleaner($_POST["email"]):"";
$message=isset($_POST["message"])?$_POST["message"]:"";
if(empty($name)){
$error[]="Name required";
}
if(empty($email)){
$error[]="Email required";
}
if(empty($message)){
$error[]="Message required";
}
// sending back the errors
if(!empty($error)){
$errors=array("error"=>$error);
echo json_encode($errors);
}
/*returning processed data with a thank you message.*/
if(($name) && ($email)&& ($message)){
$query="insert into contact_messages(name,email,message)values('$name' ,'$email','$message')";
$result=$database->query($query);
if($result){
$message[]="thank you";
$m=array("message"=>$message);
echo json_encode($m);
}
}
javascript
$(document).ready(function (){
$('form').submit(function (event){
event.preventDefault();
var formDetails=$(this).serialize();
$.post('page.php',formDetails,function(data){
var json=$.parseJSON(data);
if(json.error){
for(key in json){
var output=$("#man").css('display','block').append('<p>' + json[key] + '</p>');
}
}
else if(json.message){
for(key in json){
var output=$("#man").css('display','block').append('<p>' + json[key] + '</p>');
}
}
});
});
});