SxSWi day four: Javascript secrets

This sesssion was pretty much standing room only and I came in 15 minutes late.
I didn’t get to really settle in and pay attention as I’d like, so I’ll have to view the slides later (I’ll link to them because they were really frickin’ great)
This jumps around a bit, as I’m writing from memory.

  • They talk about memory leaks in IE, I dunno if the newly released Jscript 5.7 addressed what they were talking about
  • There was this very interesting part of the talk where they talk about being able to access dom elements using Xpath.
  • Apparently Xpath is faster in situations where you want to get all divs of class foo (for example)
  • With Xpath … the engine just goes and gets them, with dom it gets all the divs, then loops around and gets the ones you want
  • This can be slow when you’re dealing with a lot of elements
  • Dojo and prototype support using XPath … jquery (my darling) doesnt.
  • Only Mozilla and Opera support this (Webkit/Safari 3 finally added it) of course microsoft is miles behind … poor poor Microsoft 🙁
  • They talked about trying to isolate bugs to a line of code if preferable, when sending in bug reports
  • gzipping your javascript is better than “packing”
  • Make sure to set content headers to cache your javascript correctly
  • Computing the width of elements is tough because it is hard to know what dimension you want exactly (with padding? margins? without?

Another great session.