JavaScript Basics Skills Certification Test

- The assessment has a time limit.
- Do not use search engines or seek assistance from others.
- Once you've submitted an answer, you can go back.
- You may exit the test, but the timer will continue running.
- You have 1 attempts per assessment every 30 days.

Skills Being Assessed:

This assessment covers a broad range of JavaScript fundamentals, including:

• JavaScript Basics:
  • Syntax and placement of JavaScript code (<script> tags, external files).
  • Comments, alert() for output.
  • Variable declaration (var, let, const) and assignment.
• Data Types & Structures:
  • Primitive types: string, number, boolean, null, undefined.
  • Complex types: object, array.
  • Understanding typeof operator and NaN.
• Operators:
  • Arithmetic, assignment, comparison (loose == vs. strict ===).
  • Logical operators, string concatenation.
• Control Flow:
  • Conditional statements (if/else, switch, break).
  • Looping constructs (for, while, continue).
• Functions:
  • Declaration, invocation, and parameters.
  • Basic understanding of scope, closures, and callback functions.
• String Manipulation:
  • Common methods like toLowerCase(), toUpperCase(), charAt(), indexOf(), substr().
• Number & Math Operations:
  • Math object methods (Math.round(), Math.max(), Math.floor(), Math.ceil(), Math.random()).
  • String to number conversion (parseInt(), unary +).
  • Understanding type coercion in arithmetic operations.
• Arrays:
  • Creation, accessing elements, and determining length.
  • Common array methods (pop(), push(), slice(), shift(), unshift(), sort(), join(), forEach(), Array.isArray()).
• Objects:
  • Object literal syntax, accessing and iterating over properties (for...in, in operator).
• DOM (Document Object Model) Manipulation:
  • Selecting elements (document.getElementById(), document.querySelector()).
  • Modifying element content (innerHTML).
  • Creating and appending elements (document.createElement(), appendChild()).
  • Removing elements (element.remove()).
• Events:
  • Handling basic user interactions (onclick, onmouseover, onkeypress).
  • Understanding event bubbling (conceptual).
• Browser Object Model (BOM):
  • Interacting with the browser window (window.open(), window.location.href).
  • Detecting browser information (navigator.appName).
• Timers:
  • Using setTimeout(), setInterval(), and clearing them (clearTimeout(), clearInterval()).
• JSON:
  • Parsing JSON strings (JSON.parse()).
  • Converting JavaScript objects to JSON strings (JSON.stringify()).
• Scope & this keyword:
  • Basic understanding of let vs. var (block vs. function scope).
  • Conceptual understanding of the this keyword.
• Strict Mode:
  • Purpose of "use strict".
• ES6 Basics:
  • Basic class declaration syntax.

What to Review Before You Start:

To perform your best, we recommend you refresh your knowledge on:

• Core JavaScript syntax: Variable declaration, function definition, operators, and control flow statements.
• Fundamental data types: How they work and how to manipulate them, especially strings, numbers, and arrays.
• Object literals and array manipulation: Creating, accessing, and using common methods.
• DOM interaction: Selecting elements, changing their content, and responding to basic user events.
• Type coercion and comparison: The difference between == and ===, and how JavaScript handles types in operations.
• Basic scope rules and the this keyword.
• Common built-in methods for Math, String, and Array objects.
• JSON and its interaction with JavaScript objects.

Good luck with your assessment!

Web developers who have at least a basic knowledge of JavaScript and want to see where they currently stand.