Comments on: Eeking out performance in script loading

By: adohall

adohall — Mon, 05 Jan 2009 02:08:06 +0000

Someone had to be a pedant. Today it’s me. Shouldn’t your title be “eking out performance…”? http://dictionary.reference.com/browse/eke
btw I liked the article.

By: oopstudios

oopstudios — Wed, 31 Dec 2008 03:21:48 +0000

I must say that these are VERY VERY VERY good techniques, not only for speed, but also SEO and website management. I use the same technique throughout my flat-file driven site and it keeps it very maintainable!

By: Spocke

Spocke — Tue, 30 Dec 2008 17:41:33 +0000

@matanlurey/V1: I can’t manage to get it working correctly. I guess it depends on the script size and how fast it’s being parsed. I tested this by loading pretty large scripts 100k or more. If I remember correctly it only returned some other ready state than IE 7 and that state is before the file is parsed and executed and any other state never happened. So the only way to know when it’s loaded is to timeout wait for it or load it through a XHR and a eval call.

By: V1

V1 — Tue, 30 Dec 2008 10:05:18 +0000

@matanlurey
Yes it does work in IE6.

By: matanlurey

matanlurey — Mon, 29 Dec 2008 19:08:29 +0000

@Spocke:
Are you sure? I remember onreadystatechange working for script tags in IE6.
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Can anybody verify this on the top of their head>

By: slightlyoff

slightlyoff — Mon, 29 Dec 2008 17:19:56 +0000

This behavior is part of the reason that James Burke’s excellent work on the x-domain package loader for Dojo has proven to be such a performance win. It gives this this async technique to Dojo package authors for free so long as they x-domain enable their builds or use Dojo packages off of Google or AOL’s CDN.

Regards

By: BenGerrissen

BenGerrissen — Mon, 29 Dec 2008 14:32:40 +0000

In many cases, you want the script to be present and ready on the initial pageload. Clients typically want their GUI applications to be nearly instantanious, especially with enterprise websites.
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You gain faster pageloads, but if for example you use unobtrusive javascript to physically change the visual layout, you will have to be very confident in the next meeting with the client when you explain why the page jumps around like mad on each pageload.
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Use these techniques where they CAN be used, not everywhere. Fall back on gzip and minimizing as much as you can otherwise.
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This is more of a warning then an opinion, I’ve already had some issues with it 1 year ago and had to replace all the fancy smart techniques with dumb old ones.

By: Spocke

Spocke — Mon, 29 Dec 2008 14:26:42 +0000

The onreadystatechange method would be the best one just a bummer that it doesn’t work correctly on IE 6. I tried making a cross domain loading method for scripts using this method but the problem is that IE 6 fires the load event when the script file is loaded and not after it’s parsed and executed. So if you load scripts in a specific order things tends to break. The method works perfectly fine on other browsers and IE 7.

By: TNO

TNO — Mon, 29 Dec 2008 14:20:34 +0000

Why not use XHR to load an array of urls (excluding cross domain issues)? You can asynchronously import 6 or so simultaneously, build a document fragment containing the script tags and finally append the fragment to the page when they all arrive.