[20][21] The key innovation was just-in-time compilation (JIT),[22] so other browser vendors needed to overhaul their engines for JIT.[23]. During the period of Internet Explorer dominance in the early 2000s, client-side scripting was stagnant. Now let’s see … For example, a script could generate a pop-up alert box message, or provide a d In JavaScript, most of the time there is no explicit type information available. [78] Google Chrome similarly confines its page renderers to their own "sandbox". This sample code displays various JavaScript features. Historically, some JavaScript engines supported these non-standard features: Variables in JavaScript can be defined using either the var,[58] let[59] or const[60] keywords. (not not) operator in JavaScript?