Introduction To Javascript

Series

• Introduction To FrontEnd Web Development
• Introduction to HTML
• Introduction to CSS
• Introduction to Javascript
• Introduction to CSS Layout

Goals

The goal of this post is to introduce JavaScript to absolute beginners in a simple and easy-to-understand way. By the end of this post, you will have a clear idea of what JavaScript is, why it is important for building websites, and what it can do.

Target audience

This post is specifically for:

• Absolute beginners who have no prior knowledge or understanding of JavaScript or programming in general.
• Who are curious about JavaScript and want to learn more about it.

What JavaScript is

JavaScript is a flexible scripting or programming language that allows you to add advanced features to web pages. When a web page goes beyond showing static information and starts offering dynamic elements like timely updates, interactive maps, animated graphics, or scrolling video jukeboxes, JavaScript is usually involved. It's the language that enables these interactive and engaging experiences on the web.

This entire web page is typically static, meaning that the content remains fixed and doesn't change. However, there is one exception: the red button displayed below. You can click on the button, and its text color will dynamically change from red to blue. Go ahead and give it a try!

<button 
  style="color: red" 
  onclick="this.style.color='blue';"
  >Welcome to blog: Introduction to Javascript</button>

What JavaScript can do or why we need it?

JavaScript is incredibly important for frontend web development because it helps us create amazing user experiences. Here's why we need JavaScript:

Making Websites Interactive:

JavaScript allows us to add interactive elements to our websites. We can create forms that validate user input, sliders that let users adjust settings, and dropdown menus that respond to their selections. These interactive features make websites more user-friendly and engaging.

Updating Content in Real-Time:

With JavaScript, we can update parts of a web page without refreshing the whole thing. This means we can display live data, like stock prices or social media feeds, that automatically update as new information comes in. It makes our websites feel dynamic and up-to-date.

Changing Web Page Elements:

JavaScript gives us the power to modify the elements on a web page. We can change the content, style, and behavior of different parts of the page based on user interactions or other factors. This helps us create websites that respond to user actions and provide a personalized experience.

Responding to User Actions:

When users click a button, type in a form, or scroll a page, JavaScript lets us respond to those actions. We can write code that executes specific tasks or displays certain content when users interact with our website. It adds interactivity and makes our websites more intuitive.

All of the above examples demonstrate how JavaScript responds when a user clicks on a specific button. These examples are associated with an onclick event, which triggers the JavaScript code when the button is clicked.

Adding Animations and Effects:

JavaScript enables us to create eye-catching animations and visual effects. We can make elements fade in and out, slide across the screen, or respond to mouse movements. These animations and effects make our websites more visually appealing and memorable.

Compatibility with Different Browsers:

JavaScript works seamlessly across different web browsers, ensuring that our code functions properly no matter which browser our users prefer. It's a reliable language that allows us to build websites that work consistently for everyone.

Example

/// find, in the current web page browser, the first `<button>` tag 
const para = document.querySelector("button");
 
// when user click it, then trigger function `updateName`
para.addEventListener("click", updateName);
 
function updateName() {
  // open a browser default prompt dialog, to ask for name
  const name = prompt("Enter a new name");
 
  // then change the text content of the `<button>` with new-entered name
  para.textContent = `Player 1: ${name}`;
}

Sumary

To summarize, JavaScript is crucial for frontend web development as it enables us to create interactive and dynamic websites. It allows us to add interactive features, update content in real-time, modify web page elements, respond to user actions, create animations and effects, and ensure compatibility across different web browsers.

It's important to note that while JavaScript strives for compatibility, there can be slight variations in how different web browsers handle JavaScript code or support specific features. This means that sometimes things may not work exactly the same way in every situation or browser.

Nevertheless, JavaScript remains a powerful tool that empowers us to build engaging, user-friendly, and visually impressive websites. By following best practices, staying informed about browser-specific behaviors, and applying appropriate techniques for cross-browser compatibility, we can overcome these challenges and create compelling web experiences that work seamlessly for the majority of users.