Window Events

// Method 1: Load event
window.addEventListener('load', function() {
    console.log('Page fully loaded');
    // All resources loaded
});

// Method 2: DOMContentLoaded (faster)
document.addEventListener('DOMContentLoaded', function() {
    console.log('DOM ready');
    // DOM ready, images may still load
});

// Method 3: Before unload
window.addEventListener('beforeunload', function(e) {
    e.preventDefault();
    e.returnValue = ''; // Chrome requires returnValue
    return ''; // Some browsers
    // Shows confirmation dialog
});

// Method 4: Unload
window.addEventListener('unload', function() {
    console.log('Page unloading');
    // Cleanup code
});

// Method 5: Resize
window.addEventListener('resize', function() {
    console.log('Window resized');
    console.log('Width:', window.innerWidth);
    console.log('Height:', window.innerHeight);
});

// Method 6: Scroll
window.addEventListener('scroll', function() {
    console.log('Scrolled');
    console.log('Scroll Y:', window.scrollY);
    console.log('Scroll X:', window.scrollX);
});

// Method 7: Scroll with throttling
let scrollTimeout;
window.addEventListener('scroll', function() {
    clearTimeout(scrollTimeout);
    scrollTimeout = setTimeout(function() {
        console.log('Scroll ended');
    }, 150);
});

// Method 8: Visibility change
document.addEventListener('visibilitychange', function() {
    if (document.hidden) {
        console.log('Page hidden');
    } else {
        console.log('Page visible');
    }
});

// Method 9: Online/Offline
window.addEventListener('online', function() {
    console.log('Connection restored');
});

window.addEventListener('offline', function() {
    console.log('Connection lost');
});

// Method 10: Focus/Blur
window.addEventListener('focus', function() {
    console.log('Window focused');
});

window.addEventListener('blur', function() {
    console.log('Window blurred');
});

// Method 11: Hash change (URL fragment)
window.addEventListener('hashchange', function() {
    console.log('Hash changed:', window.location.hash);
});

// Method 12: Popstate (back/forward)
window.addEventListener('popstate', function(e) {
    console.log('History changed');
    console.log('State:', e.state);
});

// Method 13: Error handling
window.addEventListener('error', function(e) {
    console.error('Global error:', e.message);
    console.error('File:', e.filename);
    console.error('Line:', e.lineno);
});

window.addEventListener('unhandledrejection', function(e) {
    console.error('Unhandled promise rejection:', e.reason);
});