##Bibliotecas usadas
jQuery.ajax(): http://api.jquery.com/jquery.ajax/
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>Exemplo de validação: http://www.devmedia.com.br/jquery-validate-validando-formularios/26490
Método .vaidate(): https://jqueryvalidation.org/validate/
Não é interessante utilizar o CDN pois o site é lento
Forms Bootstrap: https://getbootstrap.com/docs/4.0/components/forms/
Buttons Bootstrap: https://getbootstrap.com/docs/4.0/components/buttons/
<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous"><script type="text/javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>Criptografias: http://blog.thiagobelem.net/criptografia-no-php-usando-md5-sha1-e-base64
Trabalhando com PDO: http://www.diogomatheus.com.br/blog/php/trabalhando-com-pdo-no-php/
Trabalhando com mysqli: http://www.codigomaster.com.br/desenvolvimento/crud-com-php-de-forma-simples-e-facil