6-12 months was a bit optimistic (I thought ES5 was released in 2011, in fact ES5 was released in 2009 and ES5.1 in 2001) for vendor adoption I'll admit. Still,

6-12 months was a bit optimistic (I thought ES5 was released in 2011, in fact ES5 was released in 2009 and ES5.1 in 2001) for vendor adoption I'll admit. Still, I can't imagine waiting more than 2-2.5 years for perhaps 80-90% of browsers supporting virtually all of ES6. > And what happens with browsers on older mobile phones that cant be upgraded ? you let your scripts stop working ? If I was absolutely worried about browser support on older mobile phones, I'd be still writing vanilla JavaScript with no features that aren't in Ecmascript 3. You'll have to drop support eventually. Plus, it's very likely a good chunk of the ES6 I'll be writing will only ever be intended for running in browsers that support other cutting-edge features like WebGL, Web Workers and WebRTC, or on a fairly up to date environment like iojs or node.js. > No,5 years after the launch of ES5 some browsers like Safari still didn't support some ES5 features. I'm not sure which features Safari is missing that you're referring to. Safari on both iOS and OS X are missing a lot of Javascript APIs, but both have fully supported ES5 since at least 2011 [0], and my old Macbook with Safari 5.1 has no problems running modern websites. > If you think you can switch to ES6 in 6 month without any kind of transpilation, while keeping a good browser compatibility good luck ... A lot of ES6 features are already being polyfilled (Typed Arrays have been polyfilled for years), plus you can use try/catch to support new syntax whilst also supplying some sort of fallback. [0] http://kangax.github.io/compat-table/es5/ http://kangax.github.io/compat-table/es5/