JavaScript Frameworks and Event Handling: The Complete 2026 Guide

What Makes a JavaScript Framework “Best” in 2026

The best JavaScript framework is the one that solves your specific problem with minimal friction. This isn’t a cop-out answer – it’s the truth that separates successful projects from abandoned ones.

Three factors determine framework excellence: developer productivity (how fast can your team ship features), runtime performance (how fast does the application run for users), and long-term maintainability (will this codebase still make sense in three years).

Enterprise teams prioritize stability and comprehensive component libraries. Startups often favor smaller, more flexible options. Agencies need frameworks that work across diverse client requirements. Your context shapes your optimal choice.

The frameworks dominating enterprise Custom software development in 2026 share common traits: strong TypeScript support, mature ecosystems, predictable release cycles, and commercial backing that ensures longevity. Ext JS leads in data-intensive business applications with 140+ pre-built enterprise components. React dominates in flexibility and ecosystem size. Angular excels in large-team environments requiring strict architectural patterns. Vue offers the gentlest learning curve without sacrificing power.

Understanding how these frameworks handle events reveals their underlying philosophies and helps predict how they’ll serve your broader application needs.

JavaScript Framework vs Library: The Distinction That Shapes Your Architecture

A library provides tools you call when needed. A JS framework calls your code within its established structure. This inversion of control fundamentally changes how you architect applications.

Libraries (jQuery, Lodash, D3.js) give you maximum flexibility. You decide the application structure, when to invoke functionality, and how pieces connect. The tradeoff: you’re responsible for architectural decisions that frameworks handle automatically.

Frameworks (Ext JS, Angular, Ember) provide the skeleton. You fill in application-specific logic within prescribed patterns. The tradeoff: less initial decision-making, but you work within the framework’s paradigms.

React occupies a middle ground – technically a library for building user interfaces, but its ecosystem (React Router, Redux, Next.js) functions as a de facto framework.

For event handling, this distinction matters significantly. Libraries give you direct DOM access and manual event management. Frameworks typically abstract event handling into their component model, providing consistency at the cost of some low-level control.

When to choose a library: You need surgical additions to existing applications, have unconventional requirements, or want maximum architectural freedom.

When to choose a framework: You’re building from scratch, need team consistency at scale, or want battle-tested patterns for common problems.

Popular JavaScript Frameworks Compared: Architecture, Performance, and Use Cases

Ext JS: Enterprise Data Applications

Ext JS provides the most comprehensive component library available – 140+ production-ready UI components including advanced grids, charts, calendars, and form elements. It uses MVVM architecture with two-way data binding.

Ideal for: Financial dashboards, healthcare systems, government applications, any scenario requiring complex data grids and strict accessibility compliance.

Event handling approach: Declarative listeners configuration within component definitions. Events bubble through component hierarchy with built-in delegation.

    Ext.create('Ext.Button', {
        text: 'Submit Report',
        renderTo: Ext.getBody(),
        listeners: {
            click: function(button, event) {
                this.fireEvent('reportSubmitted', this.getData());
            },
            mouseover: function(button) {
                button.setTooltip('Click to generate quarterly report');
            }
        }
    });

Performance characteristics: Optimized for handling thousands of data records with virtualized rendering. Larger initial payload than minimal frameworks, but superior performance in data-heavy scenarios.

React: Flexibility and Ecosystem

React’s component-based architecture with virtual DOM diffing enables efficient updates. Its unopinionated nature allows teams to choose their own state management, routing, and styling approaches.

Ideal for: Teams wanting maximum flexibility, applications requiring frequent UI updates, projects benefiting from the largest third-party ecosystem.

Event handling approach: Synthetic events that normalize browser inconsistencies. Events are pooled for performance – you must call event.persist() to retain event properties asynchronously.

    function SubmitButton({ onSubmit }) {
        const handleClick = (event) => {
            event.preventDefault();
            // React synthetic event normalizes across browsers
            onSubmit({ timestamp: event.timeStamp });
        };
        
        return <button onClick={handleClick}>Submit Report</button>;
    }

Performance characteristics: Small core library (~40kb gzipped). Virtual DOM adds overhead for simple updates but excels in complex, frequently-changing UIs.

Angular: Structured Enterprise Development

Angular provides a complete framework with built-in routing, forms, HTTP client, and testing utilities. TypeScript-first with dependency injection and decorators.

Ideal for: Large teams requiring strict architectural consistency, applications needing everything included out-of-box, organizations standardizing on TypeScript.

Event handling approach: Template-based event binding with zone.js for automatic change detection. Custom events use EventEmitter with RxJS observables.

    @Component({
        selector: 'app-submit-button',
        template: `<button (click)="handleClick($event)">Submit Report</button>`
    })
    export class SubmitButtonComponent {
        @Output() submitted = new EventEmitter<ReportData>();
        
        handleClick(event: MouseEvent): void {
            event.preventDefault();
            this.submitted.emit(this.reportData);
        }
    }

Performance characteristics: Ahead-of-time compilation reduces runtime overhead. Ivy renderer (Angular 9+) significantly reduced bundle sizes. Zone.js adds ~100kb but enables automatic change detection.

Vue: Progressive Adoption

Vue combines approachability with scalability. Single-file components encapsulate template, logic, and styling. Composition API (Vue 3) offers React-like flexibility while Options API remains available for simpler use cases.

Ideal for: Teams migrating from jQuery, projects requiring gradual adoption, developers valuing clear documentation and gentle learning curve.

Event handling approach: Template directives with modifiers for common patterns. Custom events use $emit with optional validation.

    <template>
        <button @click.prevent="handleClick" @keyup.enter="handleClick">
            Submit Report
        </button>
    </template>

    <script setup>
    const emit = defineEmits(['submitted']);

    function handleClick(event) {
        emit('submitted', { timestamp: Date.now() });
    }
    </script>

Performance characteristics: Smallest bundle size among major frameworks (~33kb gzipped). Reactive system with fine-grained dependency tracking minimizes unnecessary re-renders.

Framework Selection Matrix: Match Your Requirements

Understanding Events: The Foundation of Interactive Applications

Every user interaction – clicking a button, typing in a field, scrolling a page – generates an event. Events are the browser’s notification system, announcing that something happened and providing details about what, where, and how.

The event lifecycle follows three phases:

1. Capture phase: Event travels from the document root down to the target element
2. Target phase: Event reaches the element that triggered it
3. Bubble phase: Event travels back up from target to document root

Most developers work exclusively with the bubble phase, but understanding the complete lifecycle unlocks powerful patterns for complex applications.

Events carry rich contextual data:

    document.addEventListener('click', function(event) {
        console.log(event.type);        // "click"
        console.log(event.target);      // Element that was clicked
        console.log(event.currentTarget); // Element with the listener
        console.log(event.timeStamp);   // When it occurred
        console.log(event.clientX);     // Horizontal click position
        console.log(event.clientY);     // Vertical click position
        console.log(event.shiftKey);    // Was Shift held during click?
    });

The target vs currentTarget distinction matters for event delegation (covered below). The target is where the event originated; currentTarget is where you attached the listener.

Event Listeners: Attaching Behavior to Elements

The addEventListener method is the modern standard for event handling, replacing older inline handlers (onclick=”…”) and DOM property assignment (element.onclick = …).

Basic syntax:

    element.addEventListener(eventType, handlerFunction, options);

The options parameter accepts three configurations:

    // Boolean: use capture phase instead of bubble
    element.addEventListener('click', handler, true);

    // Object: fine-grained control
    element.addEventListener('click', handler, {
        capture: false,   // Use bubble phase (default)
        once: true,       // Remove listener after first invocation
        passive: true,    // Promise not to call preventDefault()
        signal: controller.signal  // AbortController for removal
    });

The passive option deserves special attention. When set to true, you’re promising the browser you won’t call event.preventDefault(). This allows the browser to begin handling the event (especially touch scrolling) immediately without waiting to see if you’ll prevent default behavior. For scroll and touch events on mobile, passive listeners can eliminate scroll jank entirely.

Multiple listeners on the same element execute in registration order:

    button.addEventListener('click', () => console.log('First'));
    button.addEventListener('click', () => console.log('Second'));
    button.addEventListener('click', () => console.log('Third'));
    // Click outputs: First, Second, Third

Removing listeners requires the exact same function reference:

    function handleClick() { console.log('Clicked'); }

    button.addEventListener('click', handleClick);
    button.removeEventListener('click', handleClick); // Works

    button.addEventListener('click', () => console.log('Clicked'));
    button.removeEventListener('click', () => console.log('Clicked')); // Fails - different function reference

For one-time events, prefer the once option over manual removal – it’s cleaner and handles edge cases automatically.

Event Delegation: Efficient Handling at Scale

Event delegation leverages event bubbling to handle events from multiple elements with a single listener. Instead of attaching listeners to each button, link, or list item, you attach one listener to a common ancestor.

The problem delegation solves:

    // Inefficient: listener per item
    document.querySelectorAll('.todo-item').forEach(item => {
        item.addEventListener('click', handleTodoClick);
    });

    // What happens when you add a new todo item?
    // You must manually attach another listener.

The delegation solution:

    // Efficient: one listener handles all items
    document.querySelector('.todo-list').addEventListener('click', function(event) {
        // Find the relevant target
        const todoItem = event.target.closest('.todo-item');
        if (!todoItem) return; // Click wasn't on a todo item
        
        handleTodoClick(todoItem);
    });

Benefits of delegation:

1. Memory efficiency: One listener instead of potentially hundreds
2. Dynamic content: New elements automatically handled without additional setup
3. Simplified cleanup: One listener to remove instead of tracking many
4. Centralized logic: Event handling consolidated in predictable locations

The closest() method is essential for delegation. It traverses up from the event target to find the nearest ancestor matching a selector. This handles cases where the user clicks on a child element (like an icon inside a button) rather than the delegating element directly.

    // Handles clicks on the button, or any element inside it
    document.body.addEventListener('click', function(event) {
        const button = event.target.closest('[data-action="delete"]');
        if (button) {
            const itemId = button.dataset.itemId;
            deleteItem(itemId);
        }
    });

Preventing Default Behavior and Stopping Propagation

Browsers have default behaviors for certain events: forms submit and navigate, links navigate to their href, right-clicks open context menus. Two methods control these behaviors.

event.preventDefault() stops the browser’s default action without affecting event propagation:

    // Form submission without page reload
    form.addEventListener('submit', function(event) {
        event.preventDefault();
        
        const formData = new FormData(this);
        submitFormAsync(formData);
    });

    // Link that triggers JavaScript instead of navigating
    link.addEventListener('click', function(event) {
        event.preventDefault();
        
        openModal(this.href);
    });

event.stopPropagation() prevents the event from continuing through capture or bubble phases:

    // Click on inner element won't trigger outer listener
    outer.addEventListener('click', () => console.log('Outer clicked'));

    inner.addEventListener('click', function(event) {
        event.stopPropagation();
        console.log('Inner clicked');
    });

event.stopImmediatePropagation() stops propagation AND prevents other listeners on the same element from executing:

    button.addEventListener('click', () => console.log('First'));
    button.addEventListener('click', function(event) {
        event.stopImmediatePropagation();
        console.log('Second');
    });
    button.addEventListener('click', () => console.log('Third'));
    // Click outputs: First, Second (Third never runs)

Use propagation control sparingly. It can create debugging nightmares when events mysteriously fail to trigger. Prefer conditional logic over stopping propagation when possible.

Keyboard Events: Building Accessible Interactions

Keyboard accessibility is a legal requirement in many jurisdictions and an ethical responsibility everywhere. Every interactive element must be operable via keyboard.

Three keyboard events, each with distinct use cases:

    // keydown: Fires when key is pressed, repeats if held
    input.addEventListener('keydown', function(event) {
        if (event.key === 'Escape') {
            this.blur();
        }
    });

    // keypress: Deprecated. Don't use for new code.

    // keyup: Fires when key is released, does not repeat
    input.addEventListener('keyup', function(event) {
        // Good for input validation after user finishes typing
        validateField(this.value);
    });

Use event.key instead of event.keyCode. The keyCode property is deprecated and returns numeric codes that vary across keyboard layouts. The key property returns the actual character or key name:

    document.addEventListener('keydown', function(event) {
        switch(event.key) {
            case 'ArrowUp':
                moveFocusUp();
                break;
            case 'ArrowDown':
                moveFocusDown();
                break;
            case 'Enter':
            case ' ': // Space
                activateCurrentItem();
                break;
            case 'Escape':
                closeModal();
                break;
        }
    });

Modifier key detection:

    document.addEventListener('keydown', function(event) {
        // Ctrl+S (or Cmd+S on Mac) to save
        if ((event.ctrlKey || event.metaKey) && event.key === 's') {
            event.preventDefault();
            saveDocument();
        }
        
        // Shift+Enter for different behavior
        if (event.shiftKey && event.key === 'Enter') {
            insertLineBreak();
        }
    });

Critical accessibility pattern – ensure clickable elements work with keyboard:

    customButton.addEventListener('keydown', function(event) {
        if (event.key === 'Enter' || event.key === ' ') {
            event.preventDefault();
            this.click();
        }
    });

Touch and Mobile Events: Responsive Interactions

Touch events enable swipe gestures, pinch-to-zoom, and touch-optimized interfaces. Understanding the differences from mouse events prevents common mobile bugs.

Core touch events:

    element.addEventListener('touchstart', function(event) {
        // One or more fingers touched the screen
        const touch = event.touches[0];
        startX = touch.clientX;
        startY = touch.clientY;
    });

    element.addEventListener('touchmove', function(event) {
        // Finger(s) moved while touching
        const touch = event.touches[0];
        const deltaX = touch.clientX - startX;
        const deltaY = touch.clientY - startY;
        
        // Prevent scroll while dragging element
        if (isDragging) event.preventDefault();
    });

    element.addEventListener('touchend', function(event) {
        // Finger(s) lifted from screen
        // event.touches is now empty
        // event.changedTouches contains the ended touches
    });

    element.addEventListener('touchcancel', function(event) {
        // System interrupted touch (e.g., incoming call)
        resetDragState();
    });

The 300ms click delay: Mobile browsers historically waited 300ms after tap to ensure the user wasn’t double-tapping to zoom. Modern solution:

This meta tag tells the browser your site is responsive, eliminating the delay.

Pointer events unify mouse, touch, and stylus:

    element.addEventListener('pointerdown', handleStart);
    element.addEventListener('pointermove', handleMove);
    element.addEventListener('pointerup', handleEnd);
    element.addEventListener('pointercancel', handleCancel);

Pointer events are the modern recommendation for new code – they work identically across input types, reducing code duplication.

Custom Events: Application-Specific Communication

Custom events decouple components, enabling communication without tight dependencies. A form component can announce completion without knowing what happens next.

Creating and dispatching custom events:

    // Create event with custom data
    const orderEvent = new CustomEvent('orderSubmitted', {
        detail: {
            orderId: 'ORD-12345',
            items: cart.items,
            total: cart.total
        },
        bubbles: true,      // Allow event delegation
        cancelable: true    // Allow preventDefault()
    });

    // Dispatch from the relevant element
    orderForm.dispatchEvent(orderEvent);

Listening for custom events:

    document.addEventListener('orderSubmitted', function(event) {
        analytics.track('Order Placed', event.detail);
        notifications.show(`Order ${event.detail.orderId} confirmed!`);
    });

    // Prevent default action if needed
    orderForm.addEventListener('orderSubmitted', function(event) {
        if (!validateOrder(event.detail)) {
            event.preventDefault();
        }
    });

Checking if preventDefault was called:

    const canProceed = orderForm.dispatchEvent(orderEvent);
    if (canProceed) {
        // No listener called preventDefault
        processOrder(orderEvent.detail);
    }

Enterprise pattern – event bus for cross-component communication:

    const EventBus = {
        events: {},
        
        on(event, callback) {
            if (!this.events[event]) this.events[event] = [];
            this.events[event].push(callback);
            return () => this.off(event, callback);
        },
        
        off(event, callback) {
            if (!this.events[event]) return;
            this.events[event] = this.events[event].filter(cb => cb !== callback);
        },
        
        emit(event, data) {
            if (!this.events[event]) return;
            this.events[event].forEach(callback => callback(data));
        }
    };

    // Usage
    const unsubscribe = EventBus.on('userLoggedIn', user => {
        updateNavigation(user);
    });

    EventBus.emit('userLoggedIn', { id: 1, name: 'Alex' });

    // Cleanup
    unsubscribe();

Performance Optimization: Event Handling at Scale

Poor event handling is a common source of performance problems, especially in applications with many interactive elements or frequent events like scroll and resize.

Debouncing: Delay Until Activity Stops

Debouncing waits for a pause in events before executing. Ideal for search inputs, window resizing, and form validation.

    function debounce(func, wait) {
        let timeout;
        return function executedFunction(...args) {
            clearTimeout(timeout);
            timeout = setTimeout(() => func.apply(this, args), wait);
        };
    }

    // Only search after user stops typing for 300ms
    searchInput.addEventListener('input', debounce(function() {
        performSearch(this.value);
    }, 300));

Throttling: Limit Execution Frequency

Throttling ensures a function runs at most once per time period. Ideal for scroll handlers and continuous events.

    function throttle(func, limit) {
        let inThrottle;
        return function executedFunction(...args) {
            if (!inThrottle) {
                func.apply(this, args);
                inThrottle = true;
                setTimeout(() => inThrottle = false, limit);
            }
        };
    }

    // Update position at most every 100ms during scroll
    window.addEventListener('scroll', throttle(function() {
        updateParallaxPositions();
    }, 100));

Passive Event Listeners

Declare listeners as passive when you won’t prevent default behavior:

    // Enables smooth scrolling - browser doesn't wait for your code
    document.addEventListener('scroll', handleScroll, { passive: true });
    document.addEventListener('touchmove', handleTouch, { passive: true });

Remove Listeners When No Longer Needed

Memory leaks occur when listeners persist after elements are removed:

    // Bad: listener orphaned when modal is removed from DOM
    modal.querySelector('.close').addEventListener('click', closeModal);

    // Good: cleanup when modal closes
    const abortController = new AbortController();

    modal.querySelector('.close').addEventListener('click', closeModal, {
        signal: abortController.signal
    });

    function closeModal() {
        abortController.abort(); // Removes all listeners using this signal
        modal.remove();
    }

Avoid Expensive Operations in Event Handlers

    // Bad: layout thrashing in scroll handler
    window.addEventListener('scroll', function() {
        elements.forEach(el => {
            el.style.transform = `translateY(${window.scrollY * 0.5}px)`;
            const height = el.offsetHeight; // Forces layout recalculation
        });
    });

    // Good: batch reads then writes
    window.addEventListener('scroll', function() {
        const scrollY = window.scrollY;
        
        // Use requestAnimationFrame for visual updates
        requestAnimationFrame(() => {
            elements.forEach(el => {
                el.style.transform = `translateY(${scrollY * 0.5}px)`;
            });
        });
    });

Testing Event-Driven Code

Robust applications require tested event handlers. Modern testing frameworks provide utilities for simulating user interactions.

Unit testing event handlers:

    // Jest example
    test('form submission prevents default and calls API', () => {
        const mockSubmit = jest.fn();
        const form = document.createElement('form');
        
        form.addEventListener('submit', function(event) {
            event.preventDefault();
            mockSubmit(new FormData(this));
        });
        
        const event = new Event('submit', { cancelable: true });
        form.dispatchEvent(event);
        
        expect(event.defaultPrevented).toBe(true);
        expect(mockSubmit).toHaveBeenCalled();
    });

Integration testing with Testing Library:

    import { render, screen, fireEvent } from '@testing-library/react';

    test('clicking submit button shows confirmation', async () => {
        render();
        
        fireEvent.click(screen.getByRole('button', { name: /submit/i }));
        
        expect(await screen.findByText(/order confirmed/i)).toBeInTheDocument();
    });

End-to-end testing with Playwright:

    test('user can complete checkout flow', async ({ page }) => {
        await page.goto('/checkout');
        await page.fill('[name="email"]', '[email protected]');
        await page.click('button[type="submit"]');
        await expect(page.locator('.confirmation')).toBeVisible();
    });

Debugging Event Issues

Common problems and their solutions:

“My event handler isn’t firing”

1. Check selector matches element (document.querySelector returns null?)
2. Verify event type spelling (onclick in addEventListener is wrong – use click)
3. Confirm handler is attached before event occurs (script loading order)
4. Check for stopPropagation() in ancestor listeners

“Handler fires multiple times”

1. Event listener added multiple times (common in SPAs during re-renders)
2. Event bubbling triggers handlers on multiple ancestors
3. Solution: use AbortController or track attachment state

“preventDefault() isn’t working”

1. Listener marked as passive (can’t prevent in passive listeners)
2. Event not cancelable (check event.cancelable)
3. Default already occurred before your listener ran

Browser DevTools debugging:

    // Log all events on an element
    monitorEvents(document.querySelector('#myElement'));

    // Log specific events
    monitorEvents(document.querySelector('#myElement'), ['click', 'keydown']);

    // Stop monitoring
    unmonitorEvents(document.querySelector('#myElement'));

Event Handling in Ext JS: Enterprise Patterns

Ext JS implements a sophisticated event system designed for complex enterprise applications. Events flow through the component hierarchy with built-in delegation and lifecycle management.

Component events with configuration:

    Ext.create('Ext.form.Panel', {
        title: 'User Registration',
        items: [{
            xtype: 'textfield',
            name: 'email',
            fieldLabel: 'Email',
            listeners: {
                change: function(field, newValue, oldValue) {
                    this.up('form').validateEmail(newValue);
                },
                blur: 'onEmailBlur'  // String references controller method
            }
        }],
    
        listeners: {
            beforesubmit: function(form, action) {
                // Return false to prevent submission
                return form.isValid();
            }
        }
    });

Controller-based event handling (MVVM pattern):

    Ext.define('MyApp.view.RegistrationController', {
        extend: 'Ext.app.ViewController',
        alias: 'controller.registration',
        
        onEmailBlur: function(field) {
            this.checkEmailAvailability(field.getValue());
        },
        
        onSubmitClick: function() {
            const form = this.getView();
            if (form.isValid()) {
                form.submit({
                    success: this.onSubmitSuccess,
                    failure: this.onSubmitFailure,
                    scope: this
                });
            }
        }
    });

Custom component events:

    Ext.define('MyApp.view.CustomSlider', {
        extend: 'Ext.Component',
        
        config: {
            value: 0
        },
        
        updateValue: function(newValue, oldValue) {
            this.fireEvent('valuechange', this, newValue, oldValue);
        }
    });

    // Usage
    slider.on('valuechange', function(slider, newValue, oldValue) {
        console.log(`Value changed from ${oldValue} to ${newValue}`);
    });

Event domains for application-wide events:

    // Fire application event
    this.fireEvent('userLoggedIn', userData);

    // Listen in any controller
    Ext.define('MyApp.controller.Navigation', {
        extend: 'Ext.app.Controller',
        
        listen: {
            controller: {
                '*': {
                    userLoggedIn: 'onUserLoggedIn'
                }
            }
        }
    });

Quick Reference: Event Handling Cheat Sheet

Conclusion: Building Event-Driven Excellence

Event handling transforms static HTML into living Web applications. The principles remain consistent across frameworks: listen for user actions, respond appropriately, and manage complexity through patterns like delegation and custom events.

Your framework choice should align with your team’s needs and project requirements. Ext JS excels when you need comprehensive enterprise components with sophisticated data handling. React offers unmatched flexibility and ecosystem breadth. Angular provides structured consistency for large teams. Vue delivers approachability without sacrificing capability.

Regardless of framework, the fundamentals in this guide – understanding event flow, implementing delegation, optimizing performance, and testing thoroughly – will serve you across every JavaScript project.

Ready to build enterprise-grade applications with professional event handling? Start your free Ext JS trial and experience how 140+ pre-built components accelerate Custom software development while maintaining the performance your users expect.

Frequently Asked Questions

What is the difference between event bubbling and capturing?

Bubbling moves from the target element upward through ancestors. Capturing moves from the document root downward to the target. Bubbling is the default and handles most use cases. Use capturing (third parameter true in addEventListener) when you need to intercept events before they reach descendants.

How do I handle events on dynamically created elements?

Use event delegation. Attach the listener to a stable ancestor element that exists when your JavaScript runs. Use event.target.closest() to identify which dynamic element was actually clicked.

Should I use arrow functions or regular functions for event handlers?

Arrow functions inherit this from their enclosing scope, which is often what you want for class methods or callbacks. Regular functions have this bound to the element that received the event (when not using bind). Choose based on whether you need access to the element (this) or your component/class context.

How do I pass additional parameters to an event handler?

Three approaches: closure (element.addEventListener(‘click’, () => handler(param))), data attributes (event.target.dataset.value), or bind (handler.bind(null, param)). Data attributes are often cleanest for element-specific data.

What’s the performance impact of many event listeners?

Each listener consumes memory and adds to event dispatch overhead. For lists with hundreds of items, delegation to a parent element is measurably faster than individual listeners. Use browser performance profiling to identify actual bottlenecks in your application.

How do I ensure my event handlers are accessible?

Ensure all clickable elements are focusable (native buttons, links, or add tabindex=”0″). Handle both click and keyboard events (keydown for Enter/Space). Provide visible focus indicators. Test with keyboard-only navigation.