Icone para mostrar validação de formulários em html5

gistfile1.css

input:required:invalid, input:focus:invalid {
  background-image: url('data:image/png;base64,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');
  background-position: right top;
  background-repeat: no-repeat;
  -moz-box-shadow: none;
}
input:required:valid {
  background-image: url('data:image/png;base64,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');
  background-position: right top;
  background-repeat: no-repeat;
}