Ah, I see. The JS engine actually wasn&#x27;t changed for Edge, just the rendering engine. Chakra has been around since 2009, and was used in IE9-11. It was one a wave of new JS engines developed in response to the release of Chrome&#x2F;V8 which destroyed the previous generation of JS engines in terms of performance (I&#x27;m sure the various browser vendors would say they always planned to create faster JS engines, but there&#x27;s no doubt that the release of Chrome&#x2F;V8 in 2008 accelerated their efforts).