Why this minified code run slowly in Opera Browser?

Question

I am testing JavaScript minifiers: Yahoo! YUI Compressor and Google Closure Compiler, comparing the visual result in http://text-compare.com and comparing the performance results in http://jsperf.com. In all browsers I've tested, the minified version get best results, but in Opera, the Original code get best performance. Anyone know why? I am Using Opera 12.12 stable on Ubuntu 12.10. The test page is here: http://jsperf.com/closure-vs-yui

Many thanks!!!

Answer 1

JS VMs are tricky and generally have a language "sweet spot" that they tune to. All the VMs have at one time or another stumbled across a problem that generally would only appear in minified code.

It is best to file a bug with Opera.