It would be great if it was possible to do such thing as
$('input.specific-field').parsley('error', 'this is a custom error message');
...but I guess that isn't possible?
How could I achive such thing?
Parsley has some built-in ways of adding custom error messages.
var specificField = $('input.specific-field').parsley();
# add the error
window.ParsleyUI.addError(specificField, "myCustomError", 'this is a custom error message');
# remove the error
window.ParsleyUI.removeError(specificField, "myCustomError");
More info here: http://parsleyjs.org/doc/index.html#psly-ui-for-javascript
EDIT: This method is now deprecated (thanks to @giraff).