It's also in Firefox (since Firefox 13). Documentation: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map https://developer.m

It's also in Firefox (since Firefox 13). Documentation: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...