DOM Events Basics

Basic DOM event handling

BeginnerTopic: Events Programs

JavaScript DOM Events Basics Program

This program helps you to learn the fundamental structure and syntax of JavaScript programming.

// Method 1: Inline event handler (not recommended)
// <button onclick="handleClick()">Click</button>

// Method 2: addEventListener (recommended)
const button = document.getElementById('myButton');

button.addEventListener('click', function(event) {
    console.log('Button clicked!');
    console.log('Event:', event);
    console.log('Target:', event.target);
});

// Method 3: Named function
function handleClick(event) {
    console.log('Clicked!', event.target);
}

button.addEventListener('click', handleClick);

// Method 4: Arrow function
button.addEventListener('click', (e) => {
    console.log('Arrow function handler');
});

// Method 5: Multiple events
button.addEventListener('click', handleClick);
button.addEventListener('mouseenter', function() {
    console.log('Mouse entered');
});
button.addEventListener('mouseleave', function() {
    console.log('Mouse left');
});

// Method 6: Remove event listener
button.removeEventListener('click', handleClick);

// Method 7: Event object properties
button.addEventListener('click', function(e) {
    console.log('Type:', e.type);
    console.log('Target:', e.target);
    console.log('Current Target:', e.currentTarget);
    console.log('Timestamp:', e.timeStamp);
    console.log('Bubbles:', e.bubbles);
    console.log('Cancelable:', e.cancelable);
});

Output

// Output depends on user interaction

Understanding DOM Events Basics

DOM events allow interaction with web pages.

Event Types

•click: Mouse click

•mouseenter/mouseleave: Mouse hover

•keydown/keyup: Keyboard

•submit: Form submission

•load: Page loaded

•scroll: Page scrolling

addEventListener

•Preferred method

•Can add multiple handlers

•More flexible

Event Object

•type: Event type

•target: Element that triggered

•currentTarget: Element with handler

•preventDefault(): Stop default action

•stopPropagation(): Stop bubbling

Best Practices

•Use addEventListener

•Remove listeners when done

•Use event delegation for dynamic content

Let us now understand every line and the components of the above program.

Note: To write and run JavaScript programs, you need to set up the local environment on your computer. Refer to the complete article Setting up JavaScript Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your JavaScript programs.

Custom Events