Validates that the specified attributes are not blank. See [validation] for more on validations.
$.Model.validatePresenceOf(attrNames, options) -> undefined
{Array|String}
Attribute name(s) to to validate
{Object}
(optional) Options for the validations. Valid options include 'message' and 'testIf'.
{undefined}
Validates that the specified attributes are not blank. See [validation] for more on validations.