JavaScript Foundations: The Ultimate Beginner’s Guide

Explore how JavaScript handles numbers, the prompt symbol, and basic operators in the console, including addition, subtraction, multiplication, division, and modulus, while applying the PEMDAS order of operations to expressions.

Explore JavaScript comparators to produce boolean results using greater than, less than, equal, not equal, and greater than or equal to, and less than or equal to operators.

Explore how JavaScript handles strings, from creating string literals with quotes to concatenating strings and expressions, using escape sequences, and checking length, equality, and case sensitivity.

Learn how to store and manage data in JavaScript using variables, the var keyword, and the assignment operator, with camelCase names, updating values via += and ++/--, and string concatenation.

Store strings in variables and format console output with concatenation and newline characters, then compare string lengths using the length property and the greater than operator.

Learn how to build and run JavaScript source files in the browser using a script tag, connect index.html to trains.js, and organize files with a root folder and scripts subfolder.

Put JavaScript statements in a file, separate them with semicolons, and print results to the console using console.log, illustrating how the compiler and browser console display outputs.

Learn how a while loop runs while its condition is true, avoids infinite loops, and prints numbers 1 through 5 using initialized loop variables and a train's operational variable.

Master the for loop by initializing a counter, testing a condition, and updating the counter to repeat code, contrasting it with a while loop and applying it to train examples.

Master conditional logic in JavaScript by converting multiple loops into a single for loop that uses if and else to print whether each train is operating or not operational.

explore else-if syntax and nested conditionals with a train scenario, printing statuses for running, express, and non-operational trains, including train 10 beginning at noon.

Master complex conditionals in JavaScript by using and/or logic to handle special trains, including trains 10 and 12 beginning at noon and train 3’s Sunday-only run with day checks.

Explore built-in JavaScript functions like alert, confirm, and prompt to collect and validate user input, store it in variables, and control flow with a while loop and type checks.

Learn to build your own function declarations in JavaScript, pass inputs as parameters, use return, and create reusable code with a sum of cubes example.

Count the e's in a user-entered phrase with a complex JavaScript function, validating input and looping through characters, while explaining local and global scope.

Explore arrays by building a passenger list, accessing elements with zero-based indices, and using push and pop to manage length and contents.

Apply for loops with arrays to traverse numbers, count evens, erase odds using undefined, and build a passenger list with add and delete functions in JavaScript.

Explore function expressions in JavaScript, compare with declared functions, load on demand, and use anonymous functions, closures, and hoisting to pass functions and create on-the-fly behavior.

Explore using function expressions with the array map method to transform every element, doubling numbers, and replacing explicit loops with concise one-line functions.

Return a function from another function using function expressions and learn how closures preserve data. Build tickets from a queue with push and shift, then invoke the returned function immediately.