For ... loop in JavaScript

The for ... in loop is used to iterate over the properties of an object. When we haven't discussed the object yet, you may not feel comfortable with this loop. But once you understand how objects work in JavaScript, you will find this loop very useful.

The for . in loop is used to iterate over the properties of an object. When we haven't discussed the object yet, you may not feel comfortable with this loop. But once you understand how objects work in JavaScript, you will find this loop very useful.

Syntax

 for ( variablename in object ){ statement or block to execute }

In each iteration, an attribute from the object - the object is assigned to variablename - the variable name and this loop continue until all properties of the object are gone.

For example

You try the following example of a for . in loop. It prints the Navigator object of the web browser.

  type = "text/javascript" >

 Set the variable to different object and then try.

Result:

 Navigator Object Properties 
 serviceWorker 
 webkitPersistentStorage 
 webkitTemporaryStorage 
 geolocation 
 doNotTrack 
 onLine 
 languages 
 language 
 userAgent 
 product 
 platform 
 appVersion 
 appName 
 appCodeName 
 hardwareConcurrency 
 maxTouchPoints 
 vendorSub 
 vendor 
 productSub 
 cookieEnabled 
 mimeTypes 
 plugins 
 javaEnabled 
 getStorageUpdates 
 getGamepads 
 webkitGetUserMedia 
 vibrate 
 getBattery 
 sendBeacon 
 registerProtocolHandler 
 unregisterProtocolHandler 
 Exiting from the loop! 
 Đặt biến vào đối tượng khác và Then thử .