Nested selection

The HTML:

<p><button id="cow">Cow</button></p> <p><button id="pig">Pig</button></p> <p><button id="duck">Duck</button></p>

The JavaScript code:

function showSound() { var animal = this.id; if (animal == 'cow') { alert('Mooo'); } else { if (animal == 'pig') { alert('Oink'); } else { if (animal == 'duck') { alert('Quack'); } } } } function init() { document.getElementById('cow').onclick = showSound; document.getElementById('pig').onclick = showSound; document.getElementById('duck').onclick = showSound; } window.onload = init;