Bootstrap includes validation styles for error, warning, and success states on
form controls. To use, add .has-warning, .has-error, or .has-success to the parent
element. Any .control-label, .form-control, and .help-block within that element will
receive the validation styles.
This is a successfull help block
This is a warning help block
This is an error help block
Validation Stats with Icon
You can also add optional feedback icons with the addition of .has-feedback and
the right icon.