How to dynamically show/hide a facebook login button

Question

How can I determine via javascript if a user has logged in to my site via facebook connect or not? Based on this result, I would like to show/not show a <fb:login-button> button on the site.

If I did something like this using jquery:

<div id="login"></div>

<script>
if (notLoggedIn)
{
   $("#login").html("<fb:login-button></fb>");
}
</script>

Will it work?

Answer 1

I did It this way:

HTML:

<div id="logindisplay">
    <span id="login">
      <fb:login-button background="dark" onlogin="facebook_onlogin_ready();">
      </fb:login-button>
    </span>
</div>

js:

function updateUserBox() {
    var user_box = document.getElementById("login");
    user_box.innerHTML = "<span><fb:name uid=loggedinuser useyou='false'></fb:name><fb:profile-pic uid=loggedinuser facebook-logo='true'></fb:profile-pic></span>";
    FB.XFBML.Host.parseDomTree();
        } 

FB_RequireFeatures(["Connect"], function() {
            FB.init("appkey", "/Content/xd_receiver.htm", { "ifUserConnected": updateUserBox });
            FB.Connect.showPermissionDialog("publish_stream,status_update");
            FB.Connect.requireSession();
        });

Answer 2

I don't think jQuery will stop you from inserting non-standard HTML tags, but you'll definitely want to change your closing tag from </fb> to </fb:login-button>.

Beyond that, whenever you insert XFBML tags into your DOM after page load, you'll need to request that the FB API re-parses the DOM. This should do just that:

FB.ensureInit(function(){
  FB.XFBML.Host.parseDomTree();
});