<script type="text/javascript" src="/js/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("input").keypress(function(){
$("button").click(function(){
Enter your name: <input type="text" />
<p>Keypresses:<span>0</span></p>
<button>触发输入域的 keypress 事件</button>