For the last year or so I’ve been predominantly focused on mobile web applications. While I’m a big fan of jQuery, at it’s current revision of *32.18 KB (compressed and gzipped) I think it’s generally too big for the mobile web. That’s when I discovered Zepto, a jQuery-like library that features 90% of the same functionality at a weight of 4.8 KB (compressed and gzipped). Life was good again and I resumed working with iOS and Android web apps, bidding IE adieu.

Fast forward to now and I need to make some general web pages again for a project and I need to support IE once more. These pages have some light-to-moderate js functionality and though I could write a small library from scratch, I’d be a fool in wasting so much time, though minimally, I only need:

  • Cross-browser event support
  • Cross-browser ajax support

Though one does arguably write faster and more concisely (smaller file size) if one has:

  • A chainable API
  • A CSS selector engine

The answer? Use an older version of jQuery. jQuery 1.2.6 for example is 17.18 KB (compressed and gzipped). Almost half as small as the current version. It gives me all four requirements above. Every version of jQuery has been battle-hardened against the most finicky older browsers and the newest batch of browsers aren’t really causing too much trouble. I had been writing with Zepto in Chrome initially when I made the switch to test in IE. I made the switch to 1.2.6 without issue. IE and all browsers are happy.

While I would love to take credit for thinking this through, it actually happened by accident. I referenced jQuery version 1.2.6 from Google’s CDN instead of 1.6.2.

I’m sure someone’s going to comment how I’m missing some major optimizations in later versions, but after trying the project out, I already have split second performance using an old build. If I start doing crazy animations or need .live, I’ll move up some revisions. If you do plan to try this out for yourself, know that jQuery 1.3 (20.08 KB) is when Sizzle was introduced and in jQuery 1.6 a lot of the API was modified or had signature changes (nothing that’s affected me so far).

Here’s a list of some versions along with their file sizes. Check the blog for more details.
1.6.2 (32.18 KB) – misc small bugfixes
1.5 (30.12 KB) – ajax timeout and abort
1.4.2 (24.86 KB) – .delegate
1.4 (27.25 KB) – extended .live support
1.3 (20.08 KB) – Sizzle and Live
1.2.6 (17.18) – 100% faster events
1.2 (17.21 KB)

And don’t forget if you’re using Google’s CDN (a good idea), always fallback to your own version, too, just in case.

*2.6.1, I use Charles Debugging Proxy for measurements.