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The for each...in statement is deprecated as the part of ECMA-357 (E4X) standard. E4X support has been removed. Consider using for...of instead.

Firefox now warns about the usage of for each...in and it no longer works starting with Firefox 57.
Please see Warning: JavaScript 1.6's for-each-in loops are deprecated for migration help.

The for each...in statement iterates a specified variable over all values of object's properties. For each distinct property, a specified statement is executed.


for each (variable in object) {
Variable to iterate over property values, optionally declared with the var keyword. This variable is local to the function, not to the loop.
Object for which the properties are iterated.
A statement to execute for each property. To execute multiple statements within the loop, use a block statement ({ ... }) to group those statements.


Some built-in properties are not iterated over. These include all built-in methods of objects, e.g. String's indexOf method. However, all user-defined properties are iterated over.


Using for each...in

Warning: Never use a loop like this on arrays. Only use it on objects. See for...in for more details.

The following snippet iterates over an object's properties, calculating their sum:

var sum = 0;
var obj = {prop1: 5, prop2: 13, prop3: 8};

for each (var item in obj) {
  sum += item;

console.log(sum); // logs "26", which is 5+13+8


Not part of a current ECMA-262 specification. Implemented in JavaScript 1.6 and deprecated.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support No No1.5 — 57 No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support No No No4 — 57 No No No

See also

  • for...in - a similar statement that iterates over the property names.
  • for...of - a similar statement that iterates over the property values but can only be used for iteratable types, so not for generic objects
  • for

Etiquetas do documento e contribuidores

 Última atualização por: fscholz,