Why does Google Chrome still support __proto__?

__proto__ is depr开发者_开发知识库ecated. Why do big browsers like Google Chrome still use it? Are there any plans to dump it?

One of the hardest thing to do in a language / framework is actually remove a deprecated feature. There is still loads of code in the world which depends on this feature. Removing it will break websites. Chrome has apparently looked at the cost of maintenance vs. the pain /cost of removal and chosen maintenance.

__proto__ is not only deprecated, it was actually never part of the standard. Removing the feature from Chrome would mean that some pages would no longer work in Chrome, and there is no reason to break these pages.

The feature has been added to JavaScript (ECAMScript 5) as the 'getPrototypeOf' function, and new JavaScript programs should use that instead.

A proto pseudo property has been included in §B.3.1 of the draft ECMAScript ed. 6 specification (note that the specification codifies what is already in implementations and what webites may currently rely on).

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Object/proto