<html>
<head>
<link type="text/css" rel="stylesheet" href="css/testaJavaScript.css">
</head>
<body>

<input id="msg" value="">
<button onclick="meuAlerta()" name="">Clique aqui.</button>
<div id="msgResposta"></div>


</body>
<script type="text/javascript" src="jquery-3.1.1.js"></script>
<script type="text/javascript" src="js/testaJavaScript.js"></script>
</html>