title: ajax call to send access token fail
body: <p>Hello I'm trying to allow login in my app through facebook, and than I want to get some info with the access token I'm getting.</p>
  
  <p>I'm trying to pass the access token from facebook js sdk to a webmethod on the server for me to use it later, but the call is failing.</p>
  
  <p><strong>here's my aspx:</strong></p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
  &lt;title&gt;Facebook Login Authentication Example&lt;/title&gt;
  &lt;script type="text/javascript" src="http://code.jquery.com/jquery-latest.js"&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;script&gt;
  
  
      // Load the SDK Asynchronously
      (function (d) {
          var js, id = 'facebook-jssdk', ref = d.getElementsByTagName('script')[0];
          if (d.getElementById(id)) { return; }
          js = d.createElement('script'); js.id = id; js.async = true;
          js.src = "//connect.facebook.net/en_US/all.js";
          ref.parentNode.insertBefore(js, ref);
      }(document));
  
      // Init the SDK upon load
      window.fbAsyncInit = function () {
          FB.init({
              appId: '474928559284763', // App ID
              channelUrl: '//' + window.location.hostname + '/channel', // Path to your Channel File
              status: true, // check login status
              cookie: true, // enable cookies to allow the server to access the session
              xfbml: true  // parse XFBML
          });
  
          // listen for and handle auth.statusChange events
          FB.Event.subscribe('auth.statusChange', function (response) {
              if (response.authResponse) {
                  // user has auth'd your app and is logged into Facebook
  
                  var dataString = JSON.stringify({ access_T: response.authResponse.accessToken });
                  alert(dataString);
                  $.ajax({
                      type: "POST",
                      async: false,
                      url: "Default2.aspx/save_access_token",
                      data: dataString,
                      contentType: "application/json; charset=utf-8",
                      dataType: "json",
                      success: function (result) {
  
  
                      },
                      error: function (result) {
                          alert(result.d);
                      }
                  });
  
  
                  FB.api('/me', function (me) {
                      if (me.name) {
                          document.getElementById('auth-displayname').innerHTML = me.name;
  
  
                      }
                  })
                  document.getElementById('auth-loggedout').style.display = 'none';
                  document.getElementById('auth-loggedin').style.display = 'block';
              } else {
                  // user has not auth'd your app, or is not logged into Facebook
                  document.getElementById('auth-loggedout').style.display = 'block';
                  document.getElementById('auth-loggedin').style.display = 'none';
              }
              //here
  
              //
              $("#auth-logoutlink").click(function () { FB.logout(function () { window.location.reload(); }); });
          });
      }
  &lt;/script&gt;
  &lt;h1&gt;
  Facebook Login Authentication Example&lt;/h1&gt;
  &lt;div id="auth-status"&gt;
  &lt;div id="auth-loggedout"&gt;
  
  &lt;div class="fb-login-button" autologoutlink="true" scope="email,user_checkins"&gt;Login with Facebook&lt;/div&gt;
  &lt;/div&gt;
  &lt;div id="auth-loggedin" style="display: none"&gt;
  Hi, &lt;span id="auth-displayname"&gt;&lt;/span&gt;(&lt;a href="#" id="auth-logoutlink"&gt;logout&lt;/a&gt;)
  &lt;/div&gt;
  &lt;/div&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p><strong>here's my webmethod:</strong></p>
  
  <pre><code>[WebMethod(EnableSession = true)]
      public static void save_access_token(string access_T)
      {
          HttpContext.Current.Session["a_t"] = access_T;
      }
  </code></pre>
  
  <p><strong>EDIT:</strong></p>
  
  <p>I checked to see what is written on the post and here it is:</p>
  
  <p><img src="https://i.stack.imgur.com/NlXnQ.jpg" alt="enter image description here"></p>