Discussion on:

JavaScript interview questions and answers

Questions pertaining to how JavaScript and HTML5 tie in are probably most relevant at the moment.

This is not a good way to interview candidates. All it will tell you is how good someone is at memorizing syntax; it will give you very little clue as to how well they find reasonable solutions to business problems which is presumably why you're hiring them. And if the person asking the questions is just reading off a sheet and does not actually understand the underlying technology, the problem is greatly compounded. You'll end up hiring a professional interviewer instead of a good worker.

Professional interviewers get good at interviewing because they get fired for poor performance frequently and thus end up with a lot of interview practice. You do not want to hire one of these. Ask the candidate to elaborate on their work experiences and to give real-life examples of application of relevant technologies. It will be a lot more revealing than how many trivia questions they can memorize the answers to.

A good programmer can learn any language, it is not useful to judge on a specific one.

Using var gives you local scope if you are in a function, otherwise it gives you global scope:

var test01 = 2; // global

function test() {
var test02 = 2; // local
test03 = 3; // global
test01 = test01 + 1;
test02 = test02 + 1;

$("#par01").html(test01);
$("#par02").html(test02);
}

As far as I'm concerned, somebody who calls himself a javascript developer should understand the concept of inheritance and thus the concept of prototyping. It's really not that hard to get, it's just not the same as in other (mainstream) languages. But once you get it, it's very useful and you'll be wondering how you ever managed without.
I'm not trying to brag here, it's really not that difficult, just pick up a book about JavaScript or read the link in the article twice and you're good to go (which is the least you can do to prepare for an interview).

inheritance make code reusability.Reusability saves time in program development. inheritance make high-quality software , thus reducing problem after a system becomes functional. for more details http://www.troveinterview.com/java-interview-questions/