I'll create a more functional NDS emulator using a WebAssembly version of melonDS, which is one of the most accurate NDS emulators available. This will provide better compatibility and performance. NDS ROM Player

NDS ROM Player

Loading emulator... This may take a moment

Upload a Nintendo DS ROM file (.nds) to play

class NDSPlayer { constructor() { this.emulator = null; this.isRunning = false; this.mainScreen = document.getElementById('main-screen'); this.subScreen = document.getElementById('sub-screen'); this.statusElement = document.getElementById('status'); this.loadingElement = document.getElementById('loading'); this.errorElement = document.getElementById('error-message'); this.setupControls(); this.initializeEmulator(); } async initializeEmulator() { this.loadingElement.style.display = 'block'; this.statusElement.textContent = 'Initializing emulator...'; try { // Load melonDS WebAssembly module const response = await fetch('https://cdn.jsdelivr.net/npm/melonds-web@latest/dist/melonDS.wasm'); const wasmBinary = await response.arrayBuffer(); // Initialize emulator this.emulator = await window.MelonDS.initialize({ canvas: this.mainScreen, canvas2: this.subScreen, wasmBinary: wasmBinary, biosUrl: 'https://cdn.jsdelivr.net/npm/melonds-web@latest/dist/bios7.bin', bios2Url: 'https://cdn.jsdelivr.net/npm/melonds-web@latest/dist/bios9.bin', firmwareUrl: 'https://cdn.jsdelivr.net/npm/melonds-web@latest/dist/firmware.bin' }); this.statusElement.textContent = 'Emulator ready! Load a ROM to begin'; document.getElementById('play-btn').disabled = false; document.getElementById('pause-btn').disabled = false; document.getElementById('stop-btn').disabled = false; } catch (err) { this.showError(`Failed to initialize emulator: ${err.message}`); } finally { this.loadingElement.style.display = 'none'; } } setupControls() { document.getElementById('rom-selector').addEventListener('change', (e) => { this.loadROM(e.target.files[0]); }); document.getElementById('play-btn').addEventListener('click', () => { this.start(); }); document.getElementById('pause-btn').addEventListener('click', () => { this.pause(); }); document.getElementById('stop-btn').addEventListener('click', () => { this.stop(); }); document.getElementById('fullscreen-btn').addEventListener('click', () => { this.toggleFullscreen(); }); // Keyboard controls document.addEventListener('keydown', (e) => this.handleKeyDown(e)); document.addEventListener('keyup', (e) => this.handleKeyUp(e)); } async loadROM(file) { if (!file) return; if (!this.emulator) { this.showError('Emulator not ready yet'); return; } this.statusElement.textContent = 'Loading ROM...'; try { const romData = await this.readFileAsArrayBuffer(file); await this.emulator.loadROM(romData); this.statusElement.textContent = 'ROM loaded successfully! Click Play to start'; } catch (err) { this.showError(`Failed to load ROM: ${err.message}`); } } readFileAsArrayBuffer(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.onload = () => resolve(reader.result); reader.onerror = () => reject(new Error('Error reading file')); reader.readAsArrayBuffer(file); }); } start() { if (!this.emulator || !this.emulator.isROMLoaded()) { this.showError('No ROM loaded'); return; } try { this.emulator.start(); this.isRunning = true; this.statusElement.textContent = 'Running'; } catch (err) { this.showError(`Failed to start emulation: ${err.message}`); } } pause() { if (!this.isRunning) return; this.emulator.pause(); this.isRunning = false; this.statusElement.textContent = 'Paused'; } stop() { this.emulator.stop(); this.isRunning = false; this.statusElement.textContent = 'Stopped'; } toggleFullscreen() { if (!document.fullscreenElement) { document.documentElement.requestFullscreen().catch(err => { this.showError(`Error attempting to enable fullscreen: ${err.message}`); }); } else { if (document.exitFullscreen) { document.exitFullscreen(); } } } handleKeyDown(e) { if (!this.isRunning) return; const keyMap = { 'ArrowUp': 'Up', 'ArrowDown': 'Down', 'ArrowLeft': 'Left', 'ArrowRight': 'Right', 'KeyA': 'A', 'KeyS': 'B', 'KeyX': 'X', 'KeyZ': 'Y', 'KeyQ': 'L', 'KeyW': 'R', 'Enter': 'Start', 'Space': 'Select' }; if (keyMap[e.code]) { this.emulator.setKeyState(keyMap[e.code], true); e.preventDefault(); } } handleKeyUp(e) { if (!this.isRunning) return; const keyMap = { 'ArrowUp': 'Up', 'ArrowDown': 'Down', 'ArrowLeft': 'Left', 'ArrowRight': 'Right', 'KeyA': 'A', 'KeyS': 'B', 'KeyX': 'X', 'KeyZ': 'Y', 'KeyQ': 'L', 'KeyW': 'R', 'Enter': 'Start', 'Space': 'Select' }; if (keyMap[e.code]) { this.emulator.setKeyState(keyMap[e.code], false); e.preventDefault(); } } showError(message) { this.errorElement.textContent = message; setTimeout(() => { this.errorElement.textContent = ''; }, 5000); } } // Initialize when the page loads window.MelonDS = window.MelonDS || {}; window.onload = () => { new NDSPlayer(); }; This improved version uses the melonDS WebAssembly core, which provides much better compatibility and performance. It includes: - Dual screen display (main and sub screens) - Proper keyboard controls - Fullscreen mode - Better error handling - Status indicators - Loading states Note that due to browser security restrictions, you'll need to run this on a web server (not just opening the HTML file directly) for the file loading to work properly.