Comments on: Lazy Loading Asyncronous Javascript

By: DealsKing

DealsKing — Thu, 24 Feb 2011 14:58:00 +0000

You should check out the optimized GA snippet from HTML5 Boilerplate, it’s even more minimal :)

By: Emil Stenström

Emil Stenström — Tue, 09 Nov 2010 22:33:39 +0000

Hi Peter, What most people do it first try to load the jQuery script, and then check if the global object "jQuery" is defined, otherwise load it another way. Here's a thread from StackOverflow with lots of good answers: http://stackoverflow.com/questions/1014203/

By: Peter

Peter — Tue, 09 Nov 2010 16:40:17 +0000

Wow, great article Emil! I am building a website which loads a lot of scripts (jQuery, Cycle, Hyphenator, Highslide, SWFObject, GA, etc) so I need good asynchronous loading!

I have one question. Is it possible to have fallback scripts for when a external script fails to load? For example, I would like to use Google’s version of jQuery since that will already be cached by many users, but I need a local fallback version in case Google is not available (Google is blocked in several countries). However, how do I check if an asynchronous scripts is properly loaded?

Thanks anyway for the great explanation!

By: G

Thu, 04 Nov 2010 17:03:20 +0000

Thanks for the great write-up Emil.

Can you elaborate a bit on what the best-practices are for the script that gets inserted (http://yourdomain.com/script.js in your example code).

What should be in there? I tried to look into your http://static.kundo.se/embed.js code but that is minified.

Thanks in advance!

By: Using Javascript in 2011 – Best Practice – Techsnippet.com «Techsnippet

Tue, 12 Oct 2010 16:55:21 +0000

[...] There are a few approaches on Lazy Loading Javascript, one good is by Friendly Bit. [...]

By: Damien P.

Damien P. — Thu, 23 Sep 2010 14:37:20 +0000

I knew loading asyncronous javascript was difficult but i never thought someone could do it as easy as this. Thanks !

By: Nicolas

Nicolas — Sat, 18 Sep 2010 18:52:45 +0000

Thanks for this study, I love to read new articles about web performance :)

By: ??????????? ???????? ???????? ? HTML ???????? « ?????????

??????????? ???????? ???????? ? HTML ???????? « ????????? — Sat, 18 Sep 2010 17:18:31 +0000

[...] http://friendlybit.com/js/lazy-loading-asyncronous-javascript/ [...]

By: Alexander

Alexander — Sat, 18 Sep 2010 16:55:01 +0000

Thank you for such a great explanation! saved my time

By: Emil Stenström

Emil Stenström — Thu, 09 Sep 2010 15:16:44 +0000

@Aaron: No, I haven’t, sounds lite an interesting article, thanks for the tip!

By: Emil Stenström

Emil Stenström — Thu, 09 Sep 2010 15:14:32 +0000

@Martin: Good idea. Does files loaded that way block other downloads?

By: Emil Stenström

Emil Stenström — Thu, 09 Sep 2010 11:05:29 +0000

@Enrico: Thanks! I replied to your question on StackOverflow, hope it helped.

By: Enrico

Enrico — Thu, 09 Sep 2010 08:22:35 +0000

Nice article, helped me a lot.
But I encounter a problem with browser caching and the version with the onload event. The browser does then no longer recognize any changes in the loaded javascript.
I also opened a question at stackoverflow:
http://stackoverflow.com/questions/3674830/caching-problem-with-asynchronous-javascript-loading-with-onload-event

Maybe somebody knows a solution to this?

By: Martin

Martin — Tue, 07 Sep 2010 19:10:16 +0000

Nice job!

I’m using the Async pattern but I’d changed the closure statment by a setTimeout call. It’s working perfect on IE and Opera.

By: Gavin

Gavin — Thu, 02 Sep 2010 08:58:53 +0000

a great article, and great solution to a common problem.
the perfect way to include 3rd party code without affecting page load