Usually the time spent in the rest of the browser engine outweighs the time spent in JS computation. Here&#x27;s a fun experiment: open Firefox and turn off the JIT in about:config. See how much of a difference it makes in your daily browsing.<p>(NB: I&#x27;m not claiming JS performance doesn&#x27;t matter--merely that it&#x27;s only one part of the huge landscape of overall browser performance.)