$.Model.validateLengthOf(attrNames, min, max, options) -> undefined
{Array|String}
Attribute name(s) to to validate
{Number}
Minimum length (inclusive)
{Number}
Maximum length (inclusive)
{Object}
(optional) Options for the validations. Valid options include 'message' and 'testIf'.
{undefined}
Validates that the specified attributes' lengths are in the given range. See [validation] for more on validations.