<!DOCTYPE html>
<html>
<head>
<script>
function color(color) {
document.forms[0].myInput.style.background = color;
}
</script>
</head>
<body>
<form>
Write a message:<br>
<input
type="text"
onkeydown="color('yellow')"
onkeyup="color('white')"
name="myInput">
</form>
</body>
</html>