Ajax和PHP-意外行为

Question

I'm using ajax to send a request to a php page which sets a cookie and sends a message back to the browser using the echo function. But the problem is that php sets the cookie successfully but I don't get the message in echo. I've console logged the XMLHTTPRequest Object to confirm that.

Here's the php code :

    <?php header("Access-Control-Allow-Origin: *");
    session_start();
    // echo "true"; - If I put the echo here , I get the response.
    if(isset($_POST['init'])){
        $x00 = universe::decode($_POST['init']);// Just a static function call of object Universe.
        $_SESSION['id'] = $x00['id'];
        echo "true"; // This echo does not appear in the response.
    }
    ?>

The responseText is however not undefined , it's an empty string. Take a look at the Pic.

Answer 1

Found the problem , thanks for helping, guys.

What I did intinally was stringify the json data and sent it as a normal post request and expected it to work , but it didn't for some reason.

I wrote a function that sends a post request to the server.

ajax.send(x); //Send is a function of the object ajax , x is the payload.

param = {"id": "qbcd"} //json data
param=JSON.stringify(ajax.param); // converted to string.
ajax.send("init="+param); // This will send a post request to the server.

I thought it will send the post request with init being a string and then I can access the string with $_POST['init'] and use json_decode on it . But for some reason the payload contains the stringyfied json only( checked it with Chrome Dev Tools) , so now we have to access it with $_POST[0] ie, access the first element of the post array and then parse it . Post is now not an associative array ( idk why).

Thanks for commenting :) Love stackoverflow.