Are you referring to hugi (http://www.hugi.scene.org/compo/compoold.htm) ?
I believe the x86 size optimization people were doing in the 80s and 90s required a different mindset. You needed to really understand the OS environment & memory layout (e.g. putting DOS in graphics mode using a single byte).
When optimizing javascript you focus on the javascript language (e.g. what happens when you do things like undefined xor 1).
But overall you can't really compare assembly to javascript. Some things in javascript (e.g. regexp) are almost free, while defining a function requires you to write "function(){}" when it's only 2 instructions in assembly.
