The for/in loop is a for loop that is used to iterate through the variables in an object. It can iterate to through that anything that can evaluated on the left side of the assignment expression call the LValues.  Let's use the for/in loop to iterate through an object "person".

Here we created an object called "person" with three properties we are going to use the for/in loop to display the property names as well as the values of those properties

var person = new Object();

person.name = "Tech Junkie";
person.occupation = "Blogger";
person.location = "Mars";

for(var p in person)
console.log(p + ": " + person[p]);



Here is the output: