# JavaScript for/in Statement

JavaScript Statements Reference

## Example

Loop through the properties of an object:

var person = {fname:"John", lname:"Doe", age:25};
var text = "";
var x;
for (x in person) {
text += person[x];
}

The result of text will be:

John Doe 25
Try it yourself »

## Definition and Usage

The for/in statement loops through the properties of an object.

The block of code inside the loop will be executed once for each property.

JavaScript supports different kinds of loops:

- for - loops through a block of code a number of times
- for/in - loops through the properties of an object
- while - loops through a block of code while a specified condition is true
- do/while - loops through a block of code once, and then repeats the loop while a specified condition is true

Note: Do not use the for/in statement to loop through arrays where index order is important. Use the for statement instead.

## Browser Support

Statement |  |  |  |  |
--- | --- | --- | --- | --- | ---
for/in | Yes | Yes | Yes | Yes | Yes

## Syntax

for (var in object) {
code block to be executed
}

## Parameter Values

Parameter | Description
--- | ---
var | Required. A variable that iterates over the properties of an object
object | Required. The specified object that will be iterated

## Technical Details

JavaScript Version: | 1.0

## Related Pages

JavaScript Tutorial: JavaScript For Loop

JavaScript Reference: JavaScript for Statement

JavaScript Statements Reference

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