1. Introduction to CSS Grid

CSS Grid Layout is a powerful two-dimensional layout system for the web. It allows you to create complex and responsive grid-based layouts with ease. Grid Layout works with both rows and columns, providing a more flexible way to create layouts compared to traditional methods.

2. Creating Grid Layouts

To create a grid layout, you need to define a grid container and place grid items inside it.

Basic Setup

.container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(2, 100px);
    gap: 10px;
}

.item1 { grid-column: 1 / 3; grid-row: 1 / 3; }
.item2 { grid-column: 3; }
.item3 { grid-column: 3; }
.item4 { grid-column: 1 / 3; }
.item5 { grid-column: 1; }
.item6 { grid-column: 2 / 4; }
        

Responsive Layouts

@media (max-width: 600px) {
    .container {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 400px) {
    .container {
        grid-template-columns: 1fr;
    }
}
        

3. Grid Properties and Techniques

CSS Grid provides various properties to define and manage grid layouts.

Defining Columns and Rows

.grid-container {
    grid-template-columns: 100px 200px auto;
    grid-template-rows: 150px 150px;
}
        

Using Grid Template Areas

.grid-container {
    grid-template-areas:
        "header header header"
        "sidebar main main"
        "footer footer footer";
}

.header { grid-area: header; }
.sidebar { grid-area: sidebar; }
.main { grid-area: main; }
.footer { grid-area: footer; }
        

Placing Grid Items

.item1 {
    grid-column: 1 / 3;
    grid-row: 1 / 3;
}

.item2 {
    grid-row: 2;
}
        

Aligning Grid Items

.grid-container {
    align-items: center;
    justify-items: end;
}
        

Grid Gaps

.grid-container {
    gap: 20px;
}
        

Grid Template Functions

.grid-container {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
}
        

Responsive Design with Media Queries

Responsive design ensures that a website looks good on all devices. Media queries are used to apply styles based on device characteristics such as width, height, and orientation.

Example:

              
              /* Styles for devices with a max width of 600px (typically mobile devices) */
              @media (max-width: 600px) {
                body {
                  background-color: lightblue;
                }
              }
              
              /* Styles for devices with a min width of 601px and max width of 1200px (tablets and small desktops) */
              @media (min-width: 601px) and (max-width: 1200px) {
                body {
                  background-color: lightgreen;
                }
              }
              
              /* Styles for devices with a min width of 1201px (larger desktops) */
              @media (min-width: 1201px) {
                body {
                  background-color: lightcoral;
                }
              }
              
                      

CSS Animations and Transitions

CSS animations and transitions add movement and effects to elements, enhancing user experience.

Transition Example:

              
              /* CSS for transitions */
              .example-box {
                width: 100px;
                height: 100px;
                background-color: coral;
                transition: background-color 0.5s ease, transform 0.5s ease;
              }
              
              .example-box:hover {
                background-color: blue;
                transform: scale(1.2);
              }
              
                      

Animation Example:

              
              /* CSS for animations */
              @keyframes example {
                0% { transform: translateX(0); }
                50% { transform: translateX(100px); }
                100% { transform: translateX(0); }
              }
              
              .animate-box {
                width: 100px;
                height: 100px;
                background-color: green;
                animation: example 2s infinite;
              }
              
                      

Custom Properties (CSS Variables)

Custom properties (CSS variables) allow you to store values and reuse them throughout your CSS, making it easier to maintain and update styles.

              
              /* CSS for custom properties */
              :root {
                --main-bg-color: coral;
                --main-text-color: white;
                --padding: 10px;
              }
              
              .variable-example {
                background-color: var(--main-bg-color);
                color: var(--main-text-color);
                padding: var(--padding);
              }
              
                      

Defining and Invoking Functions

Functions are reusable blocks of code that perform a specific task. You can define a function and then invoke (call) it.

Example:

              // Function Declaration
              function greet(name) {
                  return "Hello, " + name + "!";
              }
              
              // Function Invocation
              console.log(greet("Alice")); // Outputs: Hello, Alice!
                      

Understanding Scope and Closures

Scope determines the accessibility of variables. Closures are functions that retain access to variables from their lexical scope, even after the function has finished executing.

Example of Scope:

              let globalVar = "I am global";
              
              function exampleFunction() {
                  let localVar = "I am local";
                  console.log(globalVar); // Accessible
                  console.log(localVar);  // Accessible
              }
              
              console.log(globalVar); // Accessible
              // console.log(localVar); // Error: localVar is not defined
                      

Example of Closures:

              function makeCounter() {
                  let count = 0;
                  return function() {
                      count++;
                      return count;
                  };
              }
              
              const counter = makeCounter();
              console.log(counter()); // Outputs: 1
              console.log(counter()); // Outputs: 2
                      

Function Expressions and Arrow Functions

Function expressions allow you to define functions as values and can be anonymous. Arrow functions provide a more concise syntax for function expressions and handle the `this` context differently.

Function Expression Example:

              const square = function(number) {
                  return number * number;
              };
              
              console.log(square(5)); // Outputs: 25
                      

Arrow Function Example:

              const multiply = (a, b) => a * b;
              
              console.log(multiply(3, 4)); // Outputs: 12
                      

JavaScript Syntax and Basics

JavaScript is a versatile programming language commonly used for web development. It allows you to create dynamic and interactive web pages.

Example:

              // This is a single-line comment
              
              /*
               This is a multi-line comment
              */
              
              console.log("Hello, world!"); // Outputs "Hello, world!" to the console
                      

Variables, Data Types, and Operators

Variables store data values. JavaScript has various data types, including numbers, strings, and booleans. Operators are used to perform operations on variables and values.

Example:

              // Variables
              let name = "Alice"; // String
              const age = 30;     // Number
              let isStudent = true; // Boolean
              
              // Operators
              let sum = 10 + 5; // Addition
              let isAdult = age > 18; // Comparison
              
              console.log(name); // Outputs: Alice
              console.log(sum); // Outputs: 15
              console.log(isAdult); // Outputs: true
                      

Basic Control Structures (Loops, Conditionals)

Control structures allow you to control the flow of your code. Conditionals execute code based on conditions, and loops repeat code multiple times.

Conditionals Example:

              let number = 20;
              
              if (number > 10) {
                  console.log("Number is greater than 10");
              } else {
                  console.log("Number is 10 or less");
              }
                      

Loops Example:

              // For Loop
              for (let i = 0; i < 5; i++) {
                  console.log("Iteration: " + i);
              }
              
              // While Loop
              let count = 0;
              while (count < 5) {
                  console.log("Count: " + count);
                  count++;
              }
                      

Common Events (click, change, input)

JavaScript supports various events such as click, change, and input, which you can handle using event listeners.

Example of Common Events:

              // Handling click event
              document.getElementById('clickButton').addEventListener('click', function() {
                  alert('Button clicked!');
              });
              
              // Handling input event
              document.getElementById('inputField').addEventListener('input', function() {
                  console.log('Input value:', this.value);
              });
              
              // Handling change event
              document.getElementById('selectBox').addEventListener('change', function() {
                  console.log('Selected value:', this.value);
              });
                      

Event Delegation and Bubbling

Event delegation is a technique to handle events at a higher level in the DOM. Event bubbling is the process where an event propagates from the target element up through its ancestors.

Example of Event Delegation and Bubbling:

              // Event delegation
              document.getElementById('parentDiv').addEventListener('click', function() {
                  alert('Parent div clicked!');
              });
              
              document.getElementById('childDiv').addEventListener('click', function(event) {
                  alert('Child div clicked!');
                  event.stopPropagation(); // Prevents the event from bubbling up
              });
                      

Creating Custom Events

You can create and dispatch custom events to handle specific interactions in your application.

Example of Creating Custom Events:

              // Creating a custom event
              const customEvent = new Event('customEvent');
              
              document.getElementById('dispatchEventButton').addEventListener('click', function() {
                  document.dispatchEvent(customEvent);
              });
              
              document.addEventListener('customEvent', function() {
                  document.getElementById('eventOutput').textContent = 'Custom event has been dispatched!';
              });
                      

Validating Form Input with JavaScript

Form validation ensures that the user inputs are in the correct format before submission. JavaScript can be used to perform client-side validation.

Example of Form Validation:

              // JavaScript for validation
              document.getElementById('contactForm').addEventListener('submit', function(event) {
                  let isValid = true;
                  const name = document.getElementById('name').value;
                  const email = document.getElementById('email').value;
              
                  // Clear previous errors
                  document.getElementById('nameError').textContent = '';
                  document.getElementById('emailError').textContent = '';
              
                  // Validate name
                  if (name.trim() === '') {
                      document.getElementById('nameError').textContent = 'Name is required.';
                      isValid = false;
                  }
              
                  // Validate email
                  if (!email.includes('@')) {
                      document.getElementById('emailError').textContent = 'Email is invalid.';
                      isValid = false;
                  }
              
                  if (!isValid) {
                      event.preventDefault(); // Prevent form submission
                  }
              });
                      

Handling Form Submission and Data

JavaScript can handle form submissions and process the data entered by the user. You can use JavaScript to send data to a server or process it locally.

Example of Handling Form Submission:

              // JavaScript to handle form submission
              document.getElementById('dataForm').addEventListener('submit', function(event) {
                  event.preventDefault(); // Prevent the form from submitting the traditional way
              
                  const username = document.getElementById('username').value;
                  const password = document.getElementById('password').value;
              
                  console.log('Username:', username);
                  console.log('Password:', password);
              
                  // Here you can send the data to a server or process it further
              });
                      

Template Literals and Destructuring

ES6 introduced template literals and destructuring for easier and more readable code.

Template Literals

Template literals allow for string interpolation and multi-line strings.

              // Example of Template Literals
              const name = 'Alice';
              const age = 30;
              const message = `Hello, my name is ${name} and I am ${age} years old.`;
              console.log(message); // Outputs: Hello, my name is Alice and I am 30 years old.
                      

Destructuring

Destructuring allows you to extract values from arrays or objects into distinct variables.

              // Example of Destructuring
              const person = { name: 'Bob', age: 25 };
              const { name, age } = person;
              console.log(name); // Outputs: Bob
              console.log(age);  // Outputs: 25
              
              const numbers = [1, 2, 3];
              const [first, second] = numbers;
              console.log(first);  // Outputs: 1
              console.log(second); // Outputs: 2
                      

Promises and Async/Await

Promises and async/await simplify handling asynchronous operations.

Promises

Promises represent a value that may be available now, or in the future, or never.

              // Example of Promises
              const fetchData = new Promise((resolve, reject) => {
                  setTimeout(() => {
                      resolve('Data fetched successfully!');
                  }, 1000);
              });
              
              fetchData.then(result => {
                  console.log(result); // Outputs: Data fetched successfully!
              }).catch(error => {
                  console.error(error);
              });
                      

Async/Await

Async/await allows you to write asynchronous code in a synchronous manner, making it more readable.

              // Example of Async/Await
              async function fetchDataAsync() {
                  try {
                      const result = await fetchData; // Using the promise from above
                      console.log(result); // Outputs: Data fetched successfully!
                  } catch (error) {
                      console.error(error);
                  }
              }
              
              fetchDataAsync();
                      

Modules and Imports/Exports

ES6 introduced modules to organize code into reusable components.

Modules

Modules allow you to export and import functionalities between different files.

              // Example of Exporting (module1.js)
              export const greeting = 'Hello, world!';
              
              // Example of Importing (module2.js)
              import { greeting } from './module1.js';
              console.log(greeting); // Outputs: Hello, world!