To optimize such scenarios, Chakra performs only the most basic syntax-only parsing of the source code. The rest of the work (building the abstract syntax tree and generating bytecode) is performed one function at a time only when the function is about to be invoked. This strategy not only helps with the responsiveness of the browser when loading Web pages, but also reduces the memory footprint.
If Microsoft would address the archaic extensibility model in Internet Explorer, I’d probably be using it to type this post right now. Given replacements for the dozen-ish essential extensions I use in Chrome, I could see myself being tempted to switch back to IE after ten years of Firefox and Chrome.
The landscape today is reminiscent of how things were shaping up just before so many of us began switching from Netscape to IE5/6, way back when. Never underestimate how fiercely Microsoft can compete and innovate when an entire division of the company commits to winning.