Comment manipuler le DOM en utilisant JavaScript sans jQuery ?

Learning about the Document Object Model (DOM) was like discovering the blueprint of a webpage's inner workings. At first, using JavaScript to interact with it seemed like learning a secret language. But as I practiced with methods like document.getElementById() and document.querySelector(), it became clearer. One project that really clicked for me was when I had to update text on the page based on user actions. It was challenging, but using textContent to make those changes directly felt like unlocking a superpower. Now, I see the DOM as my toolkit for building interactive web experiences. It's like having the keys to customize and shape how users engage with the content on a webpage.

When I started coding, the Document Object Model (DOM) seemed like a maze. But as I learned to use Document.getElementById() and document.querySelector(), it was such an ease. In one project, I needed to update text when a button was clicked. It was not easy. I figured it out, and I got it working by using the textContent property to change the text directly.

As developers, we frequently dive into manipulating the Document Object Model (DOM) to breathe life into our web applications. While jQuery has long been a go-to for DOM manipulation, understanding how to wield the power of JavaScript alone is essential, especially for those starting out in web development. The DOM acts as a bridge between JavaScript and HTML, representing the structure of web documents as a tree-like hierarchy of nodes. JavaScript offers native methods to select and manipulate these nodes, enabling us to dynamically alter the content and behavior of our web pages.

Understanding the DOM is crucial for web developers as it forms the backbone of any web application, allowing dynamic content manipulation. JavaScript's power to interact with the DOM without relying on libraries like jQuery simplifies web development by reducing dependencies and improving load times. Mastering DOM manipulation through native JavaScript methods such as document.getElementById or querySelector can significantly enhance the performance and responsiveness of web applications.

You can manipulate the DOM using plain JavaScript methods like getElementById, querySelector, and createElement, eliminating the need for jQuery's abstraction layer.

In JavaScript, you can manipulate the DOM directly using methods like `getElementById`, `querySelector`, `appendChild`, `removeChild`, `setAttribute`, `addEventListener`, etc. No need for jQuery!

// 1. Get the element by its ID var element = document.getElementById('myElement'); // 2. Change its text content element.textContent = 'New Text'; // 3. Create a new element var newElement = document.createElement('div'); // 4. Add content to the new element newElement.textContent = 'Hello, World!'; // 5. Append the new element to an existing one element.appendChild(newElement);

Selecting Elements: jQuery: $('.class'), $('#id'), $('element') JavaScript: document.querySelector('.class'), document.getElementById('id'), document.getElementsByTagName('element') Modifying Element Content: jQuery: $('.element').html('new content'), $('.element').text('new text') JavaScript: document.querySelector('.element').innerHTML = 'new content', document.querySelector('.element').textContent = 'new text' Manipulating Styles: jQuery: $('.element').css('property', 'value') JavaScript: document.querySelector('.element').style.property = 'value'

There are many ways to change the DOM with pure JS to handle various DOM manipulations like finding an element or updating the element or its content. We must be aware of their differences to choose the best option to meet our needs. I covered some of them below👇🏻 getElementsByTagName: Returns a collection of all elements with a particular tag name. getElementById: Retrieve the first element with a specific ID. innerHTML: This property sets or gets the HTML content within an element appendChild: It adds a child element to the end of the specified parent element.

Understand the structure of the DOM, which represents the document as nodes and objects. You can access and manipulate these nodes using JavaScript. Use methods like document.getElementById(), document.getElementsByTagName(), and document.querySelector() to select elements.

Creating new elements in the DOM using JavaScript is a powerful capability, allowing developers to dynamically add content to a webpage. This process involves using methods like `createElement` to generate new nodes and `appendChild` or `insertBefore` to place them in the document. Understanding this process is crucial for building interactive, responsive web applications that can adapt their content in real-time based on user interactions or other events. It's a foundational skill in web development that enables more complex functionalities like building custom UI components or updating the page without a full reload.

// 1. Create a new element var newElement = document.createElement('div'); // 2. Set attributes if needed newElement.setAttribute('id', 'myDiv'); newElement.setAttribute('class', 'myClass'); // 3. Set content or properties newElement.textContent = 'Hello, World!'; // 4. Get the parent element var parentElement = document.getElementById('parent'); // 5. Append the new element to the parent parentElement.appendChild(newElement);

Yes, and in JavaScript, we can obtain elements from the DOM using methods like document.getElementById() or document.querySelector(). These methods allow us to pinpoint elements based on their ID, class, tag name, or other attributes. Example: // Grabbing elements by their ID const myButton = document.getElementById('myButton'); // Selecting elements via CSS selector const message = document.querySelector('#message');

JavaScript methods to create elements, but in case we have to add multiple nodes then we can use innerHTML. Here is an example simply select a div and add a table inside it // Get the div element by its ID const tableContainer = document.getElementById('tableContainer'); // Create a table as a string const tableHTML = ` <table border="1"> <thead> <tr> <th>Header 1</th> <th>Header 2</th> <th>Header 3</th> </tr> </thead> <tbody> <tr> <td>Row 1, Cell 1</td> <td>Row 1, Cell 2</td> <td>Row 1, Cell 3</td> </tr> </tbody> </table> `; // Insert the table into the div using innerHTML tableContainer.innerHTML = tableHTML;

To create new elements in the DOM, use document.createElement(element). Once created, you can add content with element.textContent or element.innerHTML, and then insert the element into the DOM using methods such as parentNode.appendChild(childNode) or parentNode.insertBefore(newNode, referenceNode).

With JavaScript's document.createElement() function, developers can dynamically expand web content, seamlessly integrating new elements with attributes and content. Using methods like appendChild() or insertBefore(), this empowers developers to enhance interactivity and responsiveness. It's akin to adding brushstrokes to a digital canvas, shaping the user experience with precision and flexibility, ensuring a dynamic and engaging web presence.

Event handling is like being the boss of a website. Imagine you have a button, and every time someone clicks it, you want something to happen, like counting how many times they clicked. This is where Event Handling is used. EventTarget.addEventListener is the most flexible way to set an event handler on an element.

Event handling is a cornerstone of dynamic web development, allowing for real-time user interaction feedback. JavaScript's ability to attach event listeners directly to DOM elements is powerful, enabling developers to create highly responsive and interactive web applications without relying on external libraries like jQuery. This approach not only simplifies the codebase but also enhances performance by reducing dependencies and overhead.

So in Layman’s language : JavaScript event handling allows us to respond to user interactions such as clicks, mouse movements, keyboard inputs, and more. By attaching event listeners to DOM elements, we can execute code in response to these interactions, enabling dynamic updates and enhancing user experience. In JavaScript, event handling starts with selecting the target element using methods like : document.getElementById(), document.querySelector(), or document.querySelectorAll(). Once we have the element, we use the addEventListener() method to attach an event listener, specifying the event type (e.g., 'click', 'mouseover') and a callback function to execute when the event occurs.

// 1. Get the element var button = document.getElementById('myButton'); // 2. Define the event listener function function handleClick(event) { console.log('Button clicked!'); } // 3. Add event listener to the element button.addEventListener('click', handleClick); // 4. Define another event listener function function handleMouseOver(event) { console.log('Mouse over button!'); } // 5. Add event listener for mouseover event button.addEventListener('mouseover', handleMouseOver);

Attach event listeners to elements to handle user interactions like clicks, keyboard input, or mouse movements. Use element.addEventListener(event, handler) to set up listeners. For example, button.addEventListener('click', function() { alert('Clicked!'); }).

Event handling in web development is akin to being the conductor of an orchestra, where each element on a webpage plays its part in harmony. With JavaScript's addEventListener() method, developers can orchestrate how elements respond to user interactions, like clicks or key presses. This method acts as a directive, specifying the event type and the action to take when the event occurs. For example, using document.getElementById('myButton').addEventListener('click', function() { alert('Button clicked!'); }) ensures that an alert pops up whenever the button with ID 'myButton' is clicked. It's like giving instructions to the elements on the page, dictating their behavior based on user actions.

Event handling in JavaScript involves capturing and responding to user interactions or other events occurring in the browser. Using addEventListner button.addEventListener('click', function(event) { console.log('Mouse coordinates:', event.clientX, event.clientY); }); Inline event Handlers <button id="myButton" onclick="alert('Button was clicked!')">Click Me</button> Removing event handlers // Remove the event listener button.removeEventListener('click', handleClick);

In one of my projects, I had to add a bit of CSS to error messages on a form. Whenever a user entered incorrect information, I wanted the corresponding text box to shake gently and catch their attention. To achieve this, I turned to JavaScript's ability to update styles dynamically. First, I selected the textbox element using document.getElementById(). Then, I applied a CSS class to it to trigger the desired animation. It was fun.

// 1. Get the element var element = document.getElementById('myElement'); // 2. Update its styles directly element.style.backgroundColor = 'blue'; element.style.color = 'white'; // 3. Alternatively, you can add or remove CSS classes element.classList.add('highlight'); element.classList.remove('old-style'); // 4. You can also toggle CSS classes element.classList.toggle('active'); // 5. Or directly manipulate specific style properties element.style.fontSize = '20px';

Modify the styles of elements dynamically using element.style. For instance, to change the color of an element, you might use element.style.color = 'blue'. This directly alters the inline styles of the element.

We can use CSS variables.CSS variables (custom properties) can be manipulated using JavaScript, allowing for more dynamic and reusable styling. Here's an example We have CSS variable --main-bg-color :root { --main-bg-color: lightblue; } #myDiv { background-color: var(--main-bg-color); } //Button to change styles. <button id="changeVariableButton">Change Variable</button> JS // Select the elements const root = document.documentElement; const changeVarButton = document.getElementById('changeVariableButton'); //Handler function function changeVariable() { root.style.setProperty('--main-bg-color', 'lightcoral'); } // Attach the event handler changeVarButton.addEventListener('click', changeVariable);

JavaScript allows for dynamic styling of webpage elements, enhancing user interaction. By directly accessing an element's style property, developers can swiftly adjust attributes like color or size. For example, document.getElementById('myElement').style.color = 'blue' instantly changes text color. Moreover, toggling classes with classList.add(), classList.remove(), or classList.toggle() enables smooth CSS transitions or animations. It's akin to wielding a stylist's brush, effortlessly crafting visually engaging web experiences.

I wanted to give users the ability to toggle between light and dark modes on a custom form. To achieve this, I utilized JavaScript's class manipulation capabilities. When a user clicked a button to switch modes, I needed to add or remove a specific class from certain elements to change their appearance accordingly. This is where JavaScript's classList property came in handy.

// 1. Get the element var element = document.getElementById('myElement'); // 2. Add a class element.classList.add('new-class'); // 3. Remove a class element.classList.remove('old-class'); // 4. Toggle a class element.classList.toggle('active'); // 5. Check if an element has a class if (element.classList.contains('some-class')) { // do something }

Classes serve as a versatile tool for managing how elements look and behave on a webpage. With JavaScript's classList property, developers can easily manipulate classes by adding, removing, or toggling them as needed. For instance, document.querySelector('.myElement').classList.add('active') swiftly activates the 'active' class for elements with the class 'myElement'. This capability proves invaluable for activating or deactivating features or styles based on user interactions. It's like having a remote control for adjusting elements' appearances and functionalities on the fly, ensuring a seamless and responsive user experience.

Beside using classList API, we can manipulate class using the class name property of an element. // Select the elements const myDiv = document.getElementById('myDiv'); //Add class to div if (!myDiv.className.includes('highlight')) { myDiv.className += ' highlight'; }

To add, remove, or toggle CSS classes, use the classList property of an element. It provides methods like element.classList.add('new-class'), element.classList.remove('old-class'), and element.classList.toggle('toggle-class').

AJAX (Asynchronous JavaScript and XML) has revolutionised web development by enabling data retrieval from servers without refreshing the entire web page. While the traditional XMLHttpRequest object paved the way, the newer fetch API offers a cleaner and more modern approach to making asynchronous requests. you can use the fetch API to handle network responses using promises, making your code cleaner and more readable. The fetch API provides a simple and powerful way to fetch resources. Example: fetch('data.json') .then(response => response.json()) // Parse the JSON response .then(data => console.log(data)) // Log the data to the console .catch(error => console.error('Error fetching data:', error)); // Handle any errors

AJAX is a technique that allows web pages to request data from a server without reloading the entire page. This makes web applications feel faster and more responsive for users. XHR - Older, well-established method - More verbose syntax - Requires event listeners for handling responses Fetch API - Modern, promise-based approach - Cleaner and more concise syntax - Handles responses with Promises (then/catch) for better async handling

Error Handling: Always include error handling when interacting with the DOM to manage exceptions and unexpected behavior. Performance: Be mindful of reflows and repaints which can impact performance. Minimize direct DOM manipulations and batch updates when possible. Accessibility: When modifying the DOM, ensure that accessibility is not compromised. Use appropriate ARIA roles and properties when changing the state or role of an element dynamically.