Notes:

JavaScript for in loop:
To traverse (or loop through) attributes of an object, we use for in loop

Objects represent real world entities.
Ex: Car, Student, College, Employee, Company, Atom, World, etc.

These real world entities can be represented in the software world using objects.

Ex:
var Car = { model: "maruti", number: "m007", color: "red" };
var Student = {rollNum:51, name:”Manjunath”, marks:85};

Objects contain collection of key (attribute) & value (attribute value) pairs.

Syntax:
for(var variableName in ObjectName)
{
statement(s);
}

Ex:
var Car = { model: "maruti", number: "m007", color: "red"}; // literal notation

for(var attribute in Car)
{
document.write(attribute, " : ",Car[attribute],"<br/>");
}
output:
model : maruti
number : m007
color : red

Ex:
var Student = { rollNum: 51, name: "Manjunath", marks: 98}; // literal notation

for(var attribute in Student)
{
document.write(Student[attribute],"<br/>");
}

Note:
It is kind of forward for loop
Limitation of for in loop is you will not be having any control over the iteration.

Interview Questions: