JavaScript For Beginners

Learn how to work with variables in JavaScript using const, let, and var to store values and reference memory. Understand how block scope versus function or global scope affects variables.

Discover how hoisting moves declarations to the top of the current scope, making var undefined until initialization while let is hoisted but not initialized.

Understand JavaScript identifiers: allowed characters include letters, digits, underscores, and dollar signs; start with a letter, dollar, or underscore; identifiers are case sensitive and reserved words are not allowed.

Learn how to enable strict mode in JavaScript with use strict, understand its benefits for beginners and experienced programmers, and avoid undeclared variables and duplicate parameters.

Build a page that accepts a price input, applies a 10 percent discount, and displays the net price when the show net price button is clicked.

Explains the javascript if statement, where a true condition triggers an action and a false condition triggers an alternative. Covers braces usage, multiple statements, and else if chains improve programs.

Learn to implement conditional discounts with if statements, starting with 20% off for prices over 1000 and 10% off for prices less than or equal to 1000, then add thresholds.

Explore switch statements in JavaScript to execute code based on a variable's value. Learn how break prevents fall-through and how default handles unmatched cases.

Explore while and for loops in JavaScript, see a for loop printing numbers 1 to 10 and their squares with a template string, and learn block-scoped let usage.

Master the while loop by starting at one, using a condition to print numbers and their squares with a template string, and incrementing to avoid infinite loops.

Use a loop to build a multiplication table from a user-entered number, up to ten rows, three columns (number, multiplier, result), triggered by a table button.

Explore strings in JavaScript: how to create, concatenate with plus, and use template literals. Learn string methods like includes, indexOf, split, substring, slice, trim, and the concept of immutability.

Practice string manipulation in JavaScript by extracting the server from an email address and validating its format, then parse comma-separated marks to compute a total.

Explore JavaScript array methods, including push, splice, indexOf, and in-place sort, and learn how string sorting follows dictionary order with case sensitivity and ASCII values.

Compute a student's total marks from a comma-separated input using a simple HTML and JavaScript setup. Convert inputs to numbers, ignore non-numbers with isNaN, and log for debugging.

Learn how sets store unique values and ignore duplicates, use add, delete, and has to manage elements, and iterate with forEach or access values for processing.

Explore maps as key-value data structures, where unique keys map to values, allow overwriting on duplicate keys, and support retrieving entries or undefined when missing.

Master regular expressions to construct patterns, validate input, and extract matches using test and exec, with digits, anchors, and meta characters for practical validation tasks.

Build a simple HTML page to enter, store, and display names. Learn to add and delete names using JavaScript array methods like push, indexOf, and splice, with proper not-found handling.

Create and manipulate a JavaScript date object using system or explicit year, month, and day values (remember month is 0–11), milliseconds since 1970, and various get/set methods, plus locale formatting.

Create an anonymous function and store it in a variable, then invoke it via that variable, a function expression.

Explore how default parameters make arguments optional by assigning default values, such as B has a default value of one. Call a function with fewer arguments to see defaults apply.

Learn how JavaScript rest parameters collect any number of arguments into a formal parameter as an array using three dots, enabling variable arguments across functions.

Learn how arrow functions provide a compact, shorthand alternative to regular functions, supporting a single expression or multiple statements, with shared parameters and no own this reference.

Learn how to use the array filter method with predicates to select odd numbers, using regular and arrow functions, and how filter returns a new array of selected elements.

Learn how to use the array find method in JavaScript to locate the first element that satisfies a predicate, with an optional index, and compare it to filter.

Explore the map method of arrays in JavaScript, learning how it takes a callback to convert each element into a new value and returns a new array of mapped results.

Learn how to use the array forEach method to process every element with a callback function, print results, or perform actions like squaring numbers, while contrasting map, filter, and find.

Explore how JavaScript handles function arguments: missing parameters become undefined, extra parameters are ignored, and use the arguments object to inspect all passed values.

Discover nested functions in JavaScript, where inner functions access outer function parameters and variables, stay private to the outer function, and are callable from within, illustrated with a React context.

Learn how a nested function becomes a closure by returning from an outer function, preserving the outer function's arguments and variables for later calls.

Learn how the spread operator uses three dots to spread arrays, creating copies rather than aliases, and apply the same concept to objects for immutable updates.

Destructuring assignment for arrays copies elements into independent variables, using defaults and the three-dots rest operator to capture, ignore, or leave values undefined.

Create and modify object literals in JavaScript without classes, access properties like name and job, and add or update fields such as salary or skills (an array).

Learn how to use the spread operator with objects to create true copies, not aliases, by spreading an existing object and adding or updating properties, with a React context.

Practice destructuring objects by extracting name and company into variables, set a default age of 30 when missing, and optionally alias properties to different variable names like n and C.

Discover how JSON became the default format for data transfer and storage, its integration with JavaScript, and the two key methods stringify and parse to convert between JSON and JavaScript.

Explore how a class serves as a template to create objects with properties and methods, using a constructor to initialize data and compute a selling price with tax.

Explain that fields are public by default and become private with a hash prefix. Demonstrate that private fields cannot be accessed from outside class, and accessing them triggers an error.

Explore how static fields, like the tax rate, belong to the class rather than objects, and how static methods are called with the class name to compute selling price.

Master error handling in JavaScript using try, catch, and finally. Access error details, show user-friendly messages, and ensure code runs after both success and failure.

Explore the browser object model and the window object, showing how global variables become window members and how to access properties like inner height, inner width, and local storage.

Learn how the location object exposes the page URL and details like host name, path name, and protocol, and use assign to load a new document into the current window.

Explore the history object in the browser object model, using history.back and history.forward to navigate back and forth with page buttons.