| CARVIEW |
JavaScript SDK: .Event.subscribe()
This method allows you to subscribe to a range of events, and define callback functions for when they fire.
FB.Event.subscribe(event, callback)
Parameters
| Name | Type | Description |
|---|---|---|
|
| The name of the event type you want to subscribe to. Click for more info. |
|
| Fired when the |
|
| Fired when the user's Facebook Login status changes. |
|
| Fired when someone logs into the app using |
|
| Fired when someone logs out of the app using |
|
| Fired when someone posts a comment using a Comments Plugin on the same page. |
|
| Fired when someone deletes a comment in a Comments Plugin on the same page. |
|
| Fired when someone likes the page using a Like button. |
|
| Fired when someone unlikes a page using a Like button. |
|
| Fired when a send button on the same page is used to share a link in a message. |
|
| Fired when FB.XFBML.parse() completes. This indicates that all of the social plugins on the page have been loaded. |
|
| This is the callback function that is triggered when the event is fired. Click for info about the different arguments and objects passed to the callbacks for each event type. You can only subscribe to global events. For example, if you have more than one Like button on your page, the same callback will be triggered no matter which is clicked. You can call add multiple callbacks to the same event, by calling |
|
| A new |
|
| A new |
|
| A new |
|
| A new |
|
| A single response object containing information about the event. |
|
|
|
|
| ID of the comment that was added. |
|
| Optional ID of the comment that this comment replied to. |
|
| A single response object containing information about the event. |
|
|
|
|
| ID of the comment that was added. |
|
| Optional ID of the comment that this comment replied to. |
|
| A |
|
| A |
|
| A |
|
| No arguments are sent to this event's callback. |
Examples
edge.create and .remove
Here's an example of a callback that can handle either the edge.create or edge.remove event:
var page_like_or_unlike_callback = function(url, html_element) {
console.log("page_like_or_unlike_callback");
console.log(url);
console.log(html_element);
}
// In your onload handler
FB.Event.subscribe('edge.create', page_like_or_unlike_callback);
FB.Event.subscribe('edge.remove', page_like_or_unlike_callback);
xfbml.render
This example will log when the page has finished rendering plugins:
var finished_rendering = function() {
console.log("finished rendering plugins");
}
// In your onload handler
FB.Event.subscribe('xfbml.render', finished_rendering);
auth.authResponseChange and auth.statusChange
The following example shows how you can track these events with a simple Facebook Login button.
// In your HTML. You must also initialize the Facebook JavaScript SDK
<fb:login-button autologoutlink="true"></fb:login-button>
// After your onload method has been called and initial login state has
// already been determined. (See above about not using these during a page's
// init function.)
FB.Event.subscribe('auth.authResponseChange', auth_response_change_callback);
FB.Event.subscribe('auth.statusChange', auth_status_change_callback);
// In your JavaScript
var auth_response_change_callback = function(response) {
console.log("auth_response_change_callback");
console.log(response);
}
var auth_status_change_callback = function(response) {
console.log("auth_status_change_callback: " + response.status);
}
After logging in you will get the following response:
"auth_response_change_callback" <-- auth response change
[object Object] <-- auth response change
"auth_status_change_callback: connected" <-- status change - connected == logged in
After logging out you will get the following response:
"auth_response_change_callback" <-- auth response change
[object Object] <-- auth response change
"auth_status_change_callback: unknown" <-- status change - unknown == logged out
auth.login and .logout
In this shortened example, you can use a small HTML fragment and the FB.login() and FB.logout() methods to trigger these events.
// In your HTML:
<input type="button" value="Login" onclick="FB.login();">
<input type="button" value="Logout" onclick="FB.logout();">
// In your onload method:
FB.Event.subscribe('auth.login', login_event);
FB.Event.subscribe('auth.logout', logout_event);
// In your JavaScript code:
var login_event = function(response) {
console.log("login_event");
console.log(response.status);
console.log(response);
}
var logout_event = function(response) {
console.log("logout_event");
console.log(response.status);
console.log(response);
}
You will get the following console output when logging in:
"logout_event"
"unknown"
[object Object]
You will get the following console output when logging out:
"login_event"
"connected"
[object Object]
comment.create and .remove
// In your HTML, include the comments plugin
<div
class="fb-comments"
data-href="https://url.to.your-page/page.html"
data-numposts="5"
data-colorscheme="light">
</div>
// In your onload method
FB.Event.subscribe('comment.create', comment_callback);
FB.Event.subscribe('comment.remove', comment_callback);
// In your JavaScript
var comment_callback = function(response) {
console.log("comment_callback");
console.log(response);
}
When creating or removing a comment, you will get the following response:
"comment_callback"
[object Object]
message.send
// In your HTML
<div class="fb-send" data-href="https://url.to.your.page/page.html" data-colorscheme="dark"></div>
// In your onload method
FB.Event.subscribe('message.send', message_send_callback);
// In your JavaScript
var message_send_callback = function(url) {
console.log("message_send_callback");
console.log(url);
}
When run, this will result in the following output to your console:
"message_send_callback"
"https://url.to.your.page/page.html"