Returning JSON data using jQuery POST function from server

I know this is old, but this is for helping all the people who might have this problem

You have to add an extra parameter ('json') to the $.post method call like this:

$.post(url,data_in,function(data_out){ your_code here },'json');

for those who don't know, your PHP must output something like this at the end of all processing:

die(json_encode(array("RESPONSE"=>"OK","MYMESSAGE"=>"THIS IS SUCCESSFULL")));

Also there is an alternative for HTML output instead of JSON:

$.post(url,data_in,function(data_out){ your_code here },'html');

then your responding PHP must output this:

echo "<div id=\"RESPONSE\">OK</div>";   
echo "<div id=\"MYMESSAGE\">THIS IS SUCCESSFULL</div>";
die();

So to respond the original question, the code must be like this:

$.post("order.php", { product: product_id, coupon: coupon }, function(data) {
    $("#price").html("$" + data.price);
    $("#discount").html("$" + data.discount);
    $("#total").html("$" + data.total);
},'json');

you're getting string from your server you should parse it as json

use

$.post("order.php", { product: product_id, coupon: coupon },
function(data) {
    data = jQuery.parseJSON( data );
    $("#price").html("$" + data.price);
    $("#discount").html("$" + data.discount);
    $("#total").html("$" + data.total);
});

you can simply use the script below just remove $array and replace it with what you want to return :

The first two headers prevent the browser from caching the response (a problem with IE and GET requests) and the third sets the correct MIME type for JSON.

let say that this is the content of the order.php file:

begin script

header('Cache-Control: no-cache, must-revalidate');
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Content-type: application/json');

$array = array("price"=>10,"product_id"=>1);
echo json_encode($array);

end script

and with :

$.post("order.php",function(data){
alert(data.price);
});

we will get 10 and that's it ,simple enough:)

Just add 'json' to the end

$.post("order.php", { product: product_id, coupon: coupon },
function(data) {
    // data.price, ..
}, 'json');

You should use $.getJSON instead of $.post to get json string.

Don't forget to set your content header to JSON