I take that back, since the util.scand method is not yet supported on iOS, but you can replace it with code that creates a valid date with the built-in Date constructor. Post again of you need help with this.
The good news, not directly related to this problem, is the event.target property is now supported as is setting the value property of a field. You previously could only get a field value. Also the setFocus field method and the doc.resetForm method are now supported.