Date Picker - Differenciate between empty and garbage data entry

[Shaun]

Greetings,

In my application I have several optional date fields.   

This is Great:  1/1/2001  (or any other valid date)
This is fine too since it's not required: ""   (nothing)
This is not ok and is Invalid:  "asdfasdfasdf"

When data binding (I use knockout with kendoUI), and when listening to the change event, there seems to be no difference between empty text, and an invalid date that has been entered.   How can I differenciate between the two?

I would like to display validation errors in the case of invalid data, or even just clear the date out when focus is lost would work as well.  

I found a similar post which directed another individual here: http://jsbin.com/ufimom/640/edit   However that is using jquery validation which I'm not interested in bringing that in to solve this issue.

Is there something obvious I'm missing here?    If it's relevant, I am using knockout and knockout-kendo libraries.

Thanks!
Shaun

[Alexander Popov]

Hello Shaun,

Here is an example that uses custom Kendo UI Validator rule to display an error message in case the input is not a valid date string. 

Regards,
Alexander Popov
Telerik