JavaScript Functions and Comments Quiz

JavaScript Overview

• JavaScript is the scripting language of the web
• Used in millions of web pages to add functionality
• Used for form validation, browser detection, and much more

JavaScript Statements

• Sequences of instructions executed in order
• Semicolons are optional, though recommended
• Single-line comments use //
• Multi-line comments use /* */

JavaScript Variables

• Containers to store data
• Case-sensitive
• Must start with a letter or underscore
• Can be declared with 'var'

JavaScript Operators

• Used to perform calculations
• Arithmetic operators (+, -, *, /, %, ++, --)
• Assignment operators (=, +=, -=, *=, /=, %=)

JavaScript Comparisons and Logical Operators

• Comparison operators (==, ===, !=, >, <, >=, <=) used to compare values
• Logical operators (&&, ||, !) used to combine or negate conditions

JavaScript If...Else Statements

• Conditional statements to perform different actions based on conditions
• 'if' statement for executing code if a condition is true
• 'if...else' statement for executing different code if a condition is false
• 'if...else if...else' statement for selecting among multiple conditions
• 'switch' statement for selecting among multiple blocks based on conditions

JavaScript Popup Boxes

• Alert, Confirm, and Prompt boxes to interact with users
• Alert displays a message
• Confirm displays a message, accepting or canceling
• Prompt lets users enter values

JavaScript Functions

• Reusable blocks of code
• Defined using 'function' keyword, followed by a name parentheses containing parameters, and curly braces containing code
• Execute when called by name
• Return values using 'return'

JavaScript Loops

• 'for' loop executes a block of code a predetermined number of times
• 'while' loop executes a block of code as long as a condition is true
• 'do...while' loop executes a block of code at least once, then repeatedly as long as a condition is true

JavaScript Break and Continue Statements

• 'break' statement exits a loop prematurely
• 'continue' statement skips the rest of the current loop iteration and proceeds to the next.

JavaScript For...In Statement

• Used to loop through elements in an array or through properties of an object

JavaScript Events

• Actions that trigger JavaScript code execution
• 'onload' or 'onunload': for page load or leaving the page respectively
• 'onfocus', 'onblur', or 'onchange': for field focus/blur/change respectively
• Event listeners can prevent or change default behaviors

JavaScript Try...Catch Statement

• Used for handling errors in code
• 'try' block contains code that might cause errors
• 'catch' block handles errors that occur in the 'try' block.

JavaScript Throw Statement

• Used to manually create an error to handle in try/catch blocks.

JavaScript Special Characters

• Use backslash () to insert special characters into strings (e.g., ' for an apostrophe, " for a double quote, \n for a new line) .

JavaScript Guidelines

• Case-sensitivity: JavaScript is case-sensitive (e.g., myFunction is different from Myfunction).
• White space: Extra spaces are ignored.
• Code lines: Break up long lines with backslashes for readability but not between functions.

JavaScript Objects

• Collections of properties and methods
• Create objects using the constructor function approach

JavaScript Number Object

• Wrapper object around primitive number values
• Methods used include but are not limited to
• toFixed(x): Formats a number with x digits after the decimal point
• toExponential(x): Formats a number in exponential notation.

JavaScript String Object

• Manages text strings and gives functions to manipulate them.
• Methods include but are not limited to
• charAt(x) returns the character at index x,
• toUpperCase(): converts to uppercase letters.

JavaScript Date Object

• Represents dates and times
• Methods include but are not limited to: setTime() to set times, getFullYear() to get the year, setDate() to set the date.

JavaScript Array Object

• Stores multiple values in a single variable
• Methods include but are not limited to: push() to add elements to the end of an array, pop() to remove an element from the end.

JavaScript Boolean Object

• Used to represent true/false values
• Methods include but are not limited to: toString() to convert a Boolean to a string,

JavaScript Math Object

• Provides mathematical functions

JavaScript RegExp Object

• Used for complex pattern matching
• Has methods like test() (returns true if the pattern matches) and exec() (returns the first match).

JavaScript Browser Detection

• Using the Navigator object, extract useful string information about the user's browser.

JavaScript Cookies

• Used to store information on the visitor's computer; accessed through the document.cookie object
• Methods include setCookie() to create and store and getCookie() to retrieve cookies.

JavaScript Form Validation

• Used to check user input for correctness before submitting a form
• Common checks include validating required fields, email addresses, and dates.

JavaScript Animation

• Modifying the src of images to create animation

JavaScript Image Maps

• Working with clickable regions within images.

JavaScript Timing Events

• Uses setTimeout() for timed execution of code
• clearTimeout() used to cancel a delayed action.

JavaScript HTML DOM Objects

• Used to access and interact with HTML elements programmatically
• Methods and properties to manipulate elements, access attributes, manage events, etc.

JavaScript Global Properties

• Infinity, NaN, undefined

JavaScript Global Functions

• Functions including decodeURI, encodeURI, escape, eval, isFinite, isNaN.

JavaScript Objects - Advanced

• Methods to create custom objects, adding properties and functions to them dynamically.

Test your knowledge on the use of comments and functions in JavaScript with this quiz. Covering single and multi-line comments, function calling, and debugging, you'll get a comprehensive understanding of these essential programming concepts. See how well you know JavaScript's syntax and functionality!