The web app I'm working on has pretty stringent performance requirements, so we do a lot of profiling in browsers (specifically FF and IE). DOM manipulation and rendering are order(s) of magnitude slower than virtually anything in plain Javascript. This has been so consistent that we've taken it as a design axiom to do as close to everything in pure JS as possible.
From this perspective, Resig is understating his point. Optimizing JS alone isn't going to deliver much; it's not close to being the bottleneck.
From this perspective, Resig is understating his point. Optimizing JS alone isn't going to deliver much; it's not close to being the bottleneck.