Hello everyone!!

We are going to learn about for-in loop in javascript.  The for (variablename in object) is cross browser technique for iterating the properties of the object which is inside the bracket. Any expression that evaluates to an object may be used as theobjectExpression. variablename is any expression that resolves to a property reference. Objects are collections of properties and every property gets its own standard set of internal properties. Once the iteration starts, the name of the next properties of the object gets assigned to the variablename.It is valid for variablename to resolve to a different reference at each iteration. 

For example:-

var a;
for(a in navigator){
document.write(a);
document.write(<br />);
}

Output:-

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