This code should update the <div> with the value the user entered when "update" is clicked, but it does not. Why, and how do you fix this? Assume you cannot change the show() function.

gistfile1.html

<div class="number"></div>
<input type="text" /><button class="update">update</button>

<script type="text/javascript">
var $number = document.querySelector('.number');
var $input = document.querySelector('input');

function show() {
	$number.innerHTML = this.value;
}
document.querySelector('button').onclick = show;
</script>