Facebook today announced a new version of its Like Box plugin that has been rewritten to load two to four times faster than the previous implementation.

The Like Box is a plugin that anyone can add to their website to attract and gain Likes for their Facebook page. Visitors can see how many users are connected to the page and which of their friends Like it. They can read recent posts from the page and Like the page with one click, without needing to leave the site they’re on.

Facebook made several changes to the plugin to help it load faster, including smaller components, smaller CSS and JavaScript size and better packaging. There are also changes that improve perceived performance. Inline CSS and non-blocking JavaScript deliver the first impression to the user faster, so even though more needs to be loaded after that, it feels even faster because users start to see some of the plugin right away.

At its most basic implementation, the Like Box now loads in 0.5 seconds, as opposed to 2.3 seconds. The perceived performance is better because the initial impression — also known as “first paint” — is now at 0.3 seconds, as opposed to 2.1 seconds.

Facebook’s first iteration of the Like Box was called Fan Box and launched in 2009.

Most websites will not have to make any changes to run the new version of the plugin. However, if they are still using the deprecated Fan Box (fb:fan or plugins/fan.php), they should switch to the Like Box (fb:likebox or plugins/likebox.php). More information about the plugin and tools to create one for your page is available here.