This is the browser running linux inside a web page!
My web browser takes 15 seconds to boot linux and the emulator runs very fast.
The file "jslinux.js" (Linux launcher) loads the linux images (vmlinux-2.6.20.bin and linuxstart.bin), creates a virtual hard disk (hda).
Try Linux inside the PC emulator here, boot from your browser: http://www.busybox.net/live_bbox/live_bbox.html
Screenshot of the browser running linux. Results of commands "cat /proc/cpuinfo", "df" and "free":