Front End Programmer Interview Preparation Guide
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Front End Programmer based Frequently Asked Questions by expert members with experience as Front End Developer. These questions and answers will help you strengthen your technical skills, prepare for the new job test and quickly revise the concepts

67 Front End Developer Questions and Answers:

1 :: What is the difference between a host object and a native object?

Native - existing in JavaScript. Host - existing in the environment.

2 :: Tell me are you familiar with Jasmine or QUnit?

Jasmine and QUnit are JavaScript testing frameworks. I would familiarize yourself with the basics.

3 :: Explain what is lazy loading?

Lazy loading is a design pattern commonly used in computer programming to defer initialization of an object until the point at which it is needed.

Lazy loading is loading code only once user needs it. For Example, there is a button on the page, which shows different layout once user pressed it. So there is no need to load code for that layout on initial page load.

4 :: Do you know what is the difference between == and === ?

== is equal to
=== is exactly equal to (value and type)

5 :: Do you know what is a closure?

Closures are expressions, usually functions, which can work with variables set within a certain context. Or, to try and make it easier, inner functions referring to local variables of its outer function create closures.

6 :: Explain the difference between == and === ?

The 3 equal signs mean "equality without type coercion". Using the triple equals, the values must be equal in type as well.

== is equal to
=== is exactly equal to (value and type)
0==false // true
0===false // false, because they are of a different type
1=="1" // true, auto type coercion
1==="1" // false, because they are of a different type

7 :: Tell me what is the difference between form get and form post?

With GET the form data is encoded into a URL by the browser. The form data is visible in the URL allowing it to be bookmarked and stored in web history. The form data is restricted to ASCII codes. Because URL lengths are limited there can be limitations on how much form data can be sent.

With POST all the name value pairs are submitted in the message body of the HTTP request which has no restrictions on the length of the string. The name value pairs cannot be seen in the web browser bar.

POST and GET correspond to different HTTP requests and they differ in how they are submitted. Since the data is encoded in differently, different decoding may be needed.

8 :: Explain what is a javascript object?

A collection of data containing both properties and methods. Each element in a document is an object. Using the DOM you can get at each of these elements/objects and do some cool sh*t.

9 :: Tell us what is the difference between HTML and XHTML?

HTML is HyperText Markup Language used to develop the website.
XHTML is modern version of HTML 4. XHTML is an HTML that follows the XML rules which should be well-formed.

10 :: What is a clear?

A clear is used when you don't want an element to wrap around another element, such as a float.