New Post: String Validation

Does anyone know why error messages clear on a valid selections on controls with numeric values but error messages don't clear on character values? Doesn't seem to matter the kind of control (drop down, text, radio). I did notice that the numeric value controls had the following attributes but the character ones did not:

data-val-required="Please select a type" data-val-number="The field must be a number." data-val="true"

Thank you.