Ajax returning object instead of data - php

Question

What is the correct way to handle Ajax success callback events using jquery?
In my code, when I run instead of displaying data, it alerts object:object. However, if I use say msg.box it returns the data correctly.
I am trying to create an if statement where if text equals a certain word then the variable from json is placed in the html of the result div BA_addbox.
I cannot seem to get this to work and would be grateful if someone could point out my error. I have only included the relevant code as the form is posting the correct data and the php code is catching all the posts. Many thanks.
ajax code
$.ajax({
type: "POST",
url: "/domain/admin/requests/boxes/boxesadd.php",
data: formdata,
dataType: 'json',
success: function(msg){
if(msg == "You need to input a box") {
$("#BA_addbox").html(msg.boxerrortext);
}
else {
$("#BA_addbox").html(msg.box);
}
//alert(msg);
console.log(msg);
//$("#BA_addbox").html(msg.box);
//$("#formImage .col_1 li").show();
//$("#BA_boxform").get(0).reset();
//$("#boxaddform").hide();
}
});
boxesadd.php
$box = mysql_real_escape_string($_POST['BA_box']);
$boxerrortext = "You need to input a box";
if (isset($_POST['submit'])) {
if (!empty($box)) {
$form = array('dept'=>$dept, 'company'=>$company, 'address'=>$address, 'service'=>$service, 'box'=>$box, 'destroydate'=>$destroydate, 'authorised'=>$authorised, 'submit'=>$submit);
$result = json_encode($form);
echo $result;
}
else
{
$error = array('boxerrortext'=>$boxerrortext);
$output = json_encode($error);
echo $output;
//echo "You need to input a box";
}
}

Answer 1

In javascript associative arrays are called objects, so there's no bug in the transmitted data.
Why do you compare msg to "You need to input a box"? You cannot compare object and string, this makes no sense.
if(typeof msg.boxerrortext !== "undefined" && msg.boxerrortext == "You need to input a box") {
$("#BA_addbox").html(msg.boxerrortext);
} else {
$("#BA_addbox").html(msg.box);
}

Answer 2

Try this instead:
if(msg.boxerrortext) {
$("#BA_addbox").html(msg.boxerrortext);
}
else {
$("#BA_addbox").html(msg.box);
}
Hope this will help !!