100+ Free JSE Certified Entry-Level JavaScript Programmer Practice Questions

Introduction to JavaScript and Computer Programming

Distinguish interpreting from compiling and client-side from server-side execution, identify the ECMAScript standard and JavaScript's history, set up a basic environment, and run code embedded in HTML with <script> or directly in the browser console.

Variables, Data Types, Type Casting, and Comments

Name, declare, and initialize variables with var, let, and const; work with primitive types (boolean, number, bigint, undefined, null) and complex types (Array, Object); use typeof; cast types with Number, String, parseInt, and parseFloat; and apply scope, shadowing, hoisting, string interpolation, and comments.

Operators and User Interaction

Classify and apply assignment, arithmetic, logical, comparison, conditional (ternary), typeof, instanceof, and delete operators; understand precedence, associativity, and grouping with parentheses; and perform two-way communication using alert, confirm, and prompt dialog boxes.

Control Flow - Conditional Execution and Loops

Branch with if-else and switch (including fall-through and break); repeat statements with for, while, and do-while loops using dependent and independent conditions; control iteration with break and continue; and reason about truthy/falsy values and infinite loops.

Functions

Decompose tasks using function declarations and expressions; pass parameters and return results; manage local variables, scope, and shadowing; and apply first-class functions, arrow functions, recursion, and synchronous and asynchronous callbacks such as setTimeout.