<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript" src="http://www.graciomar.com.br/js/jquery.min.js"></script>
<title>Exemplo Combo dependente com Jquery</title>
</head>
<body>
<h1>Exemplo Combo dependente com Jquery</h1>
Estado:
<select id="select_estado">
<option value="">Selecione o Estado</option>
<option value="BA">Bahia</option>
<option value="PE">Pernambuco</option>
<option value="RJ">Rio de Janeiro</option>
<option value="SE">Sergipe</option>
</select>
Município:
<select id="select_municipio">
<option></option>
</select>
</body>
</html>
