Facebook "like" button - facebook

Question

My facebook like button loads really slow, so as a solution I read this;
http://developers.facebook.com/docs/reference/javascript/
The only part I am confused about are these two lines;
appId : 'YOUR_APP_ID', // App ID
channelUrl : '//WWW.YOUR_DOMAIN.COM/channel.html', // Channel File
I am unsure what would go in the above.
Could someone enlighten me? Thank you .
Edit: This is how my code looks like (for facebook like button), and I know it isn't right..
<div id="fb-root"></div>
<script>
window.fbAsyncInit = function() {
FB.init({
appId : 'YOUR_APP_ID', // App ID
channelUrl : '//WWW.YOUR_DOMAIN.COM/channel.html', // Channel File
status : true, // check login status
cookie : true, // enable cookies to allow the server to access the session
xfbml : true // parse XFBML
});
// Additional initialization code here
};
// Load the SDK Asynchronously
(function(d){
var js, id = 'facebook-jssdk'; if (d.getElementById(id)) {return;}
js = d.createElement('script'); js.id = id; js.async = true;
js.src = "//connect.facebook.net/en_US/all.js";
d.getElementsByTagName('head')[0].appendChild(js);
}(document));
</script>
<script>(function(d, s, id) {
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); js.id = id;
js.src = "//connect.facebook.net/en_GB/all.js#xfbml=1";
fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script>

Answer 1

I'm not quite sure you need this.
For your like button you should be using https://developers.facebook.com/docs/reference/plugins/like/.
The FB JavaScript SDK is used when you're writing applications that would relay on data they receive from the Facebook API. In your case you're only using a "Like button". That doesn't depend on any data thus you don't need it.

Answer 2

Channel File
The channel file addresses some issues with cross domain communication in certain browsers. The contents of the channel.html file can be just a single line:
<script src="//connect.facebook.net/en_US/all.js"></script>
It is important for the channel file to be cached for as long as possible. When serving this file, you must send valid Expires headers with a long expiration period. This will ensure the channel file is cached by the browser which is important for a smooth user experience. Without proper caching, cross domain communication will become very slow and users will suffer a severely degraded experience. A simple way to do this in PHP is:
<?php
$cache_expire = 60*60*24*365;
header("Pragma: public");
header("Cache-Control: max-age=".$cache_expire);
header('Expires: ' . gmdate('D, d M Y H:i:s', time()+$cache_expire) . ' GMT');
?>
<script src="//connect.facebook.net/en_US/all.js"></script>
The channelUrl parameter is optional, but recommended. Providing a channel file can help address three specific known issues. First, pages that include code to communicate across frames may cause Social Plugins to show up as blank without a channelUrl. Second, if no channelUrl is provided and a page includes auto-playing audio or video, the user may hear two streams of audio because the page has been loaded a second time in the background for cross domain communication. Third, a channel file will prevent inclusion of extra hits in your server-side logs. If you do not specify a channelUrl, you can remove page views containing fb_xd_bust or fb_xd_fragment parameters from your logs to ensure proper counts.
The channelUrl must be a fully qualified URL matching the page on which you include the SDK. In other words, the channel file domain must include www if your site is served using www, and if you modify document.domain on your page you must make the same document.domain change in the channel.html file as well. The protocols must also match. If your page is served over https, your channelUrl must also be https. Remember to use the matching protocol for the script src as well. The sample code above uses protocol-relative URLs which should handle most https cases properly.
App Id
This is your Facebook application ID. Go to https://developers.facebook.com/apps and select the application you setup. If you didn't setup an application, then read: http://developers.facebook.com/docs/guides/canvas/

Answer 3

The page you linked to is for the Javascript SDK, which is probably not what you want, unless you want to do more than just plop a "Like" button on your page. To use the SDK, you have to have a Facebook app and add some code to your website, which is where you'll get the App ID.
The "Like" button documentation is here, and there's not a whole lot you can do to get it to load faster if it's Facebook taking a while to load the page, unless you want to add a full-fledged app and maybe use that to "Like" pages for the user, but I'm not sure if that's even possible. Pull up Firebug or Chrome Dev Tools and see what's taking the longest, but it's probably just on Facebook's end.