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.

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 . 

According to Tutorialspoint

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