Novice issue of this jQuery code not working

Novice issue of this jQuery code not working

I'm really new to jQuery, and I want this code to show an alert box when
the button is pressed.
<script src="https://code.jquery.com/jquery-1.9.1.js"></script>
<script>
$("button").click(function() {
alert("You clicked.");
});
</script>
<button>Button</button>
I try it, and nothing happens when I click the button.