Professional Courses
Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.
Categories
Interactive Games
Fun, engaging games to boost memory, math fluency, typing speed, and English skillsβperfect for learners of all ages.
Typing
Memory
Math
English Adventures
Knowledge
Enroll to start learning
Youβve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take mock test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Using getElementById
Unlock Audio Lesson
Signup and Enroll to the course for listening the Audio Lesson
Let's start with how to select an element by its ID using `getElementById`. This method retrieves a single DOM element, which must have a unique ID attribute.
What if two elements have the same ID?
Good question! IDs should always be unique in a document. If they aren't, `getElementById` will only return the first one it finds.
Can you show us an example?
Certainly! Here's a simple HTML element: `<p id='demo'>Hello</p>`. If we use `const p = document.getElementById('demo');`, we can then access and manipulate this paragraph.
So, can we also change its text?
Exactly! You can use `p.textContent = 'New Text';` to update it. Remember: ID = Unique! π―
Got it! I can remember ID stands for 'Identical Data' in some ways.
Using getElementsByClassName
Unlock Audio Lesson
Signup and Enroll to the course for listening the Audio Lesson
Next, letβs dive into using `getElementsByClassName`. This method allows us to select all elements with a specific class name.
What does it return?
It returns an HTMLCollection, a live collection of elements. So, if you add new elements with that class, they instantly become part of the collection.
Can we manipulate these selected elements too?
"Yes! If you select multiple elements, you can loop through them to change their properties. For example:
Using querySelector
Unlock Audio Lesson
Signup and Enroll to the course for listening the Audio Lesson
Now, letβs look at `querySelector`. Itβs very powerful because it allows us to use CSS selectors.
What does it select?
It selects the first element that matches a given CSS selector. For instance, `document.querySelector('.myClass')` will return the first element with the class 'myClass'.
And what about querySelectorAll?
Great follow-up! `querySelectorAll` returns a static NodeList of all elements that match the selector, allowing you to work with multiple elements directly.
So I can select and style elements based on their classes or IDs?
Exactly! Query wisely! π
Introduction & Overview
Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.
Quick Overview
Standard
This section focuses on the various methods JavaScript offers to select HTML elements, including getElementById, getElementsByClassName, and querySelector. Understanding these methods is crucial for dynamic manipulation of the DOM.
Detailed
Selecting Elements
In this section, we will explore how JavaScript can be used to select HTML elements dynamically using various methods. Understanding these selection techniques is integral to manipulating elements on a web page effectively. JavaScript provides several ways to target specific elements in the DOM:
- **`document.getElementById(
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Methods to Select Elements
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Use these methods to select HTML elements in JavaScript:
- document.getElementById("myId");
- document.getElementsByClassName("myClass");
- document.getElementsByTagName("p");
- document.querySelector(".class");
- document.querySelectorAll("div");
Detailed Explanation
In this chunk, we introduce five methods used in JavaScript to select HTML elements. These are fundamental to manipulating the DOM.
document.getElementById("myId"): This method retrieves a single element with the specified ID.document.getElementsByClassName("myClass"): This returns a list of all elements with the specified class name.document.getElementsByTagName("p"): This method returns all elements of a specified tag name (like all<p>elements).document.querySelector(".class"): This selects the first element that matches a CSS selector.document.querySelectorAll("div"): This returns a list of all elements that match a CSS selector, allowing you to select multiple elements.
These selection methods are essential as they allow you to interact with and manipulate elements on a webpage dynamically.
Examples & Analogies
Think of a webpage like a library and the elements like books. Each book has a unique ID (like a library catalog number), and you can also gather books by their genre (class) or type (like all fiction books). The selection methods are like using different search techniques to find the exact book you're interested in.
Example of Selecting an Element
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Example:
Hello
Detailed Explanation
In this example, we have a paragraph element <p> with the id "demo" that contains the text "Hello". Using the document.getElementById method, we retrieve this specific element and store it in the variable p.
The method p.textContent accesses the text content of the paragraph, which is then logged to the console. This demonstrates how to select an element and retrieve its content in JavaScript.
Examples & Analogies
Imagine you find a book in the library with the ID "demo". You pull that specific book off the shelf and open it to read the introduction. In our code, accessing the textContent is like reading the introduction of the book you just selected.
Definitions & Key Concepts
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
-
getElementById: A method for selecting an element by its unique ID.
-
getElementsByClassName: A method for getting multiple elements with the same class.
-
querySelector: A method that can select elements using CSS selectors.
-
querySelectorAll: A method to get all elements matching a CSS selector.
Examples & Real-Life Applications
See how the concepts apply in real-world scenarios to understand their practical implications.
Examples
-
Example of using getElementById:
const element = document.getElementById('myId');. -
Using querySelector to select the first
:
const p = document.querySelector('p');.
Memory Aids
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
π΅ Rhymes Time
-
Select an ID, unique and bright,
getElementById, makes it right!
π Fascinating Stories
-
Imagine you're a librarian. Each book has a unique ID. When you're looking for a specific book, you don't want to browse; you simply ask for the ID!
π§ Other Memory Gems
-
ID: Individuality Directly. Unique IDs mean selectivity!
π― Super Acronyms
CLASS
- Create Lists And Select Styles!
Flash Cards
Review key concepts with flashcards.
Glossary of Terms
Review the Definitions for terms.
-
Term: getElementById
Definition:
Selects a single DOM element based on its unique ID.
-
Term: getElementsByClassName
Definition:
Selects multiple elements that share the same class name.
-
Term: getElementsByTagName
Definition:
Selects all elements of the specified tag type.
-
Term: querySelector
Definition:
Selects the first element that matches a specific CSS selector.
-
Term: querySelectorAll
Definition:
Selects all elements that match a specific CSS selector, returning a NodeList.