Comments on: Keeping third party JavaScript from slowing down your site

By: Augustus Vais

Augustus Vais — Fri, 05 Mar 2010 01:40:54 +0000

Hello, I found this blog article while searching for help with JavaScript. I have recently switched browsers from Google Chrome to Firefox 3.2. After the change I seem to have a problem with loading JavaScript. Every time I browse page that needs Javascript, the page doesn’t load and I get a “runtime error javascript.JSException: Unknown name”. I can’t seem to find out how to fix the problem. Any aid is very appreciated! Thanks

By: cielo

cielo — Thu, 15 Oct 2009 18:42:00 +0000

Very instructive, but where in my template would I place your JavaScript code?

My poor blog is running soooo slow that I’m losing readers… HELP please!

cielo

By: jaisen

jaisen — Sun, 19 Jul 2009 05:20:20 +0000

@Dan, thanks for pointing that out. That must have got changed somehow during a save of the post. It’s fixed now.

By: Dan

Dan — Sat, 18 Jul 2009 22:43:13 +0000

Oops, comments can be exploited, too.

alert("See comments.");

By: Dan

Dan — Sat, 18 Jul 2009 22:37:49 +0000

Just a warning - your example has a script to “http://thirdparty.com/path/to/file.js” (the part isn’t escaped with <) and that destination is an ad site. They could make this page do malicious things.

By: Chris Blow

Chris Blow — Mon, 02 Jun 2008 06:51:05 +0000

@joey: the js is dynamically written from the server, so you need a “live” connection to the third party.

But WRT the security issue, you are right on to raise the issue: it was just a few months ago that perl.com was hacked because one of their ad partners (read: remote js) had their domain name expire! ….

When was the last time you checked your
“content partner’s” registration expiry? :)

By: Joey Mazzarelli

Joey Mazzarelli — Sun, 01 Jun 2008 22:52:22 +0000

Have you considered the security aspect of directly including 3rd-party scripts? You are effectively giving them the ability to steal cookies, alter the behavior of your site, read user data, etc.

It requires little effort to make a local copy of the script and use that one instead. And you don’t have to worry bad behavior (malicious or accidental) nor updates breaking your site.

Just a thought.

By: Peter Michaux

Peter Michaux — Sat, 31 May 2008 21:48:20 +0000

I don’t think using a central source for common JavaScript libraries is such a great idea. At least not in all cases. I don’t think I would use such a source.

http://peter.michaux.ca/article/7906

These startups you mention don’t want you to think about the possible costs. That would discourage adoption.

By: jaisen

jaisen — Sat, 31 May 2008 21:43:20 +0000

@Peter, the google hosted js libs are a great idea. Google’s infrastructure is as reliable and fast as you can expect from a third party.

My main concern is that startups while providing great services don’t have infrastructure that’s as reliable as one might expect. So if you *must* include their scripts it should become a standard practice to minimize your dependency on them.

I would like for these startups to address this issue instead of just giving you a script tag to paste into your site without thinking of the possible cost.

By: Peter Michaux

Peter Michaux — Sat, 31 May 2008 21:38:06 +0000

You could use this technique even for your own JavaScript files. Some people do.

There may be a trend to start using more JavaScript files from third-party servers.

http://ajaxian.com/archives/announcing-ajax-libraries-api-speed-up-your-ajax-apps-with-googles-infrastructure

I think the JavaScript files in mashups slow things down because there is database interaction to dynamically generate that JavaScript. The part that the JavaScript is from another server is probably not what makes the page painfully slow to finish loading. It may make it slower however as extra connections need to be made.