After downloading a "Compressed" build of the mootools 1.1 library (with everything included), the file size was about 40 kb (42 to be exact). But after downloading the normal (not compressed) build, the exact size was 172 kb. The non-compressed build was about 7000 lines in javascript code.

I would normally asume that parsing 7000 lines of code isn't very CPU friendly, however, the compressed build seems to be parsed on the fly.

So far I have not experienced any problems with the library (in terms of browser overhead), but I was wondering when put onto a highly active website (one that has a variety of ads, and images, fonts and colors, and of coarse content) then would the browser rendering the web page start to lag due to the massive javascript footprint of the mootools framework?

Or is it just that normal javascript is simply not that draining on browser resources? And that mootools really isn't that big of a deal in terms of browser process?

I run IE7 and FF2 on my P4 2.4Ghz, 512mb, 128mb VGA on a standard ATA IDE 120Gig Windows XP Pro PC. Both browsers interpret the mootools activity fine, but what about computers that are less high-end? Is there a ballpark system requirement to run a semi mootools coded website?

I am aware that mootools only functions on IE6 + 7, FF (not sure which versions other than 2), Opera and Safari.