2015
2 featuresJavaScript is a programming language that runs in browsers, usually through the <script> element. JavaScript has changed over many years. This feature represents the oldest language features, such as built-in objects, statements, and operators. Also known as ECMAScript.
Functions are series of statements that can be called and return a value. The function keyword (as in function () { }) and arrow (=>) expression create functions. The JavaScript functions protocol includes default and rest parameters and binding to this.
Limited Availability
11 featuresThe Temporal API allows you to work with dates, times, time zones, and durations. It is more powerful than the Date API.
The Error.isError() static method checks whether a value is an Error object.
The with JavaScript statement adds a given object to the chain of scopes used to evaluate names.
The __proto__ property of objects partially exposes the prototype of an object.
The __defineGetter__() and __defineSetter__() methods of objects bind a function to a property, which is called on setting or reading the property.
The escape() and unescape() built-in Javascript methods encode and unencode strings using percent encoding, where certain characters are replaced by hexadecimal escape sequences.
The getYear() and setYear() methods of Date objects get and set the year as an offset to 1900.
JavaScript built-in methods such as, String.bold() and String.italics(), wrap strings in (often historic) HTML.
The toGMTString() method of Date objects is an alias to the toUTCString() method.
The callee property of the arguments variable in a non-strict function body's local scope is the function that arguments belongs to.
The caller and arguments properties of a non-strict mode Function object are the function that called it and the arguments it was called with. Not to be confused with the arguments variable in a function body's local scope.