<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
	function inserirMensagem() {
		document.write("<p>ok deu tudo certo.");
	}
	
</script>
</head>
<body>
<button onclick="inserirMensagem();">Click me</button>
<script type="text/javascript" src="jquery-3.1.1.js"></script>
</body>
</html>