{jscript}

Source

A very nice source of examples can be found here.

Button, date/time, css

<button type="button" onclick="document.getElementById('demo').innerHTML = Date()">
update</button>
<button type="button" onclick="document.getElementById('demo').style.fontWeight = 'bold'">
bold</button>
<p id="demo">NA</p>

NA

Alert

<script>
window.alert("Hello, script!");
</script>