Front-end Job Interview Questions: My Answers!

This file contains my personal(some research included in 'personal') answers to a number of front-end interview questions from https://github.com/h5bp/Front-end-Developer-Interview-Questions

Table of Contents

1. General Questions
2. HTML Questions
3. CSS Questions
4. JS Questions
5. Testing Questions
6. Performance Questions
7. Network Questions
8. Coding Questions

General Questions:

• What did you learn yesterday/this week?

  Object.create is a constructor pattern created by Douglas Crockford to offer a less "obscured" method than the 'new Object'.

• What excites or interests you about coding?

  The infinite possibilities, the power of creation.

HTML Questions:

• What does a doctype do?

  Doctype is a required declaration to inform the brower the HTML version used in the page, also required for legacy reasons.

• What's the difference between full standards mode, almost standards mode and quirks mode?

  It's possible to define through the 'doctype' declaration in wich mode the template engine will operate:

  1 - Full standard mode: the behavior described by the current HTML and CSS specifications
  2 - Almost standards mode: includes some quirks implementation
  3 - Layout emulates nonstandard behavior, its used for legacy
  

CSS Questions:

• What is the difference between classes and IDs in CSS?

  1 - Class uses a period(.) followed by the name of the class, can be used on a group of elements with common attributes.

  2 - ID uses the hash(#) followed by the name of the ID, should be unique and it's more specificic than classes(overrides the same attributes setted by classes of that element).

JS Questions:

• Explain event delegation

  A pattern used to assign an event handler to the parent or a common ancestor of the elements. Is commonly used to avoid batch assignments.

Testing Questions:

• What are some advantages/disadvantages to testing your code?

  • Advantages: reduces code refactoring time, reduces long-term costs, delivery a safer code.*
  • Advantages: increases workflow complexibility, increases short-term costs.*

Performance Questions:

• What tools would you use to find a performance bug in your code?

  Chrome Devtools Timeline with the paint flashing option on.

Network Questions:

• Traditionally, why has it been better to serve site assets from multiple domains?

  HTTP1.1 can't handle multiplexing, only one request can be outstanding on a connection at a time using the current protocol. One workaround is to use multiple source domains.

Coding Questions:

• Question: What is the value of foo? *

var foo = 10 + '20';

Due to JS internal type coercion rules, the result is the string "1020"