JavaScript Programming from A-Z: Learn to Code in JavaScript

Discover how JavaScript comments work, using single-line // and multi-line /* */ notes to annotate code without changing behavior, while understanding top-to-bottom, left-to-right execution and semicolon statements.

Define a variable in JavaScript with var, name it using letters, underscores, and numbers (not starting with a number), and display it with document.write.

Explore variables and primitive types in JavaScript, including numbers (positive, negative, decimal), strings, booleans, and undefined, and store objects and functions while escaping quotes with backslashes.

Learn to declare and use variables in JavaScript, assign strings and numbers, and combine them with the plus operator to form sentences and perform arithmetic.

Learn how to create and call functions in JavaScript, building on variables, declare them with a name, parameters, and curly braces, and use alerts to display output without repeating code.

Create and call functions in JavaScript using a sample apple function and an onclick button, and connect it to a simple HTML form to run the function.

Create a JavaScript function with multiple parameters to compare items, pass different fruit arguments, and reuse the function to see results and repeated calls.

Learn how to use the return statement in JavaScript, returning a value from functions, using parameters, performing operations like addition, and displaying results on the page with document.write.

Explore how to call functions from another function in JavaScript, using Apple and orange functions, and learn how mutual calls can create an endless loop.

Explore global versus local variables in JavaScript, using a fruit variable set to Apple. See how the global variable is accessible everywhere, while the local variable works only inside functions.

Learn to use JavaScript arithmetic operators, including plus, minus, multiply, divide, and modulo, and practice with variables and shorthand assignments like += and ++ to compute and display results.

Explore assignment operators in JavaScript by updating a number variable with +=, -=, *=, and /= to demonstrate arithmetic changes and the final result remains two.

Learn how to use if statements to compare values in JavaScript and run code when conditions are true, using operators like <, >, <=, >=, and != or ===.

Learn how if-else statements control output in JavaScript by evaluating a boolean variable, using true or false conditions, and handling else branches when conditions are not met.

Learn how to nest statements inside if statements, declare variables like first name and last name, and use else to control output with document.write, demonstrating true and false conditions.

Learn how to build complex conditions in JavaScript using nested if statements and or operators. See true/false outcomes with examples like first name equals J and last name equals Cutler.

Use switch statements to replace messy if-else chains, mapping a name variable to specific outputs like eight times Mr. Olympia and handling a default case.

Learn how to use the for loop to perform repetitive tasks, such as outputting a message five times in the browser, by iterating i from 0 to 4 with i++.

Explore the while loop and compare it to the for loop, showing how to initialize a variable outside the loop, increment it, and prevent infinite loops while producing repeated output.

Learn how the do while loop executes its body before checking the condition, ensuring it runs at least once, and how it differs from for and while loops.

Explore more JavaScript event handlers like on click, on mouseover, on mouseout, on load, and on unload, and see how they trigger alerts on user interactions.

Define JavaScript objects as data with properties and methods, and show creating and accessing them using dot notation. Highlight built-in properties like length and interaction with the document object.

Create object properties using a constructor function, define name and age, and instantiate objects with new to access properties via dot notation.

Discover the easiest way to create JavaScript objects with object initializers using curly braces and dot notation to define and output properties like name and full name.

Explore how to create a JavaScript array, store a list of names, output elements on a page using indices starting at zero, and note undefined results for out-of-range indices.

Create a people array with a predefined list or empty to add items later, and learn zero-based indexing to access elements like people[0].

Learn how to work with arrays' properties and methods, including using length to count items and concat to join arrays, and practice indexing and placing elements.

Learn how to use join and pop array methods in JavaScript to output all items with a chosen separator and to remove the last element from an array.

Explore array methods in JavaScript by reversing the people array, pushing new items, and sorting elements from a to z to understand order and manipulation.

Create an array using a for loop and prompt the user three times, storing answers in a fruits array and outputting items at indexes 0, 1, and 2.

Explore how to output every element of a JavaScript array in alphabetical order using a for loop and the array's length property, with a simple document write approach.

Learn how to use associative arrays in JavaScript by mapping string keys like fruit to Apple and car to Volvo, and access values with bracket notation.

Explore JavaScript math objects, using the math object to access pi and compute square roots with sqrt, and practice declaring number and answer to output results.

Learn to use date objects in JavaScript by creating a time function that outputs the current hours, minutes, and seconds using a Date object and setInterval to update every second.

Identify forms in JavaScript by accessing document.forms, selecting the first form with index 0, and inspecting its length to verify inputs like username and email.

Learn to access and inspect forms in the document by targeting a form instance, its elements, and attributes such as name and type to retrieve user name and password.

Master simple form validation by using a validator function to check a checkbox's checked property on submit, and display alerts for true or false states.