Accessor methodsLimited availability
The __defineGetter__() and __defineSetter__() methods of objects bind a function to a property, which is called on setting or reading the property.
Not yet supported in all major browsers — check the table and provide a fallback.
Discouraged: TC39 included accessor methods in Annex B of the ECMAScript specification, which covers JavaScript features with "one or more undesirable characteristics and in the absence of legacy usage would be removed."
Browser support
DesktopChrome
1+Supportedsince Dec 11, 2008
Current: 155Edge
12+Supportedsince Jul 29, 2015
Current: 154Firefox
1+Supportedsince Nov 9, 2004
Current: 157Safari
1–2Not supported
3+Supportedsince Oct 26, 2007
Current: 27MobileChrome Android
18+Supportedsince Jun 27, 2012
Current: 155Firefox Android
4+Supportedsince Mar 29, 2011
Current: 157Safari iOS
1+Supportedsince Jun 29, 2007
Current: 27How to use
Support is still inconsistent across browsers. Use feature detection and test carefully.
Example
Full syntax and examples are on MDN: defineGetter .
Feature detection
JS · check before using
if ("defineGetter" in Object || ("prototype" in Object && "defineGetter" in Object.prototype)) {
// Object.defineGetter is available
}Documentation (MDN)
Sub-features
Support for each part of the feature (4). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| Object.defineGetter | 1 | 12 | 1 | 3 | 18 | 4 | 1 |
| Object.defineSetter | 1 | 12 | 1 | 3 | 18 | 4 | 1 |
| Object.lookupGetter | 1 | 12 | 1 | 3 | 18 | 4 | 1 |
| Object.lookupSetter | 1 | 12 | 1 | 3 | 18 | 4 | 1 |