我们可以通过设定按钮的onclick属性来给按钮绑定onclick事件
<!DOCTYPE html>
<html>
<head>
<script>
function displayDate()
{
document.getElementById("demo").innerHTML=Date();
}
</script>
</head>
<body>
<h1>My First JavaScript</h1>
<p id="demo">This is a paragraph.</p>
<button type="button" onclick="displayDate()">Display Date</button>
</body>
</html>
