This videos goes through the new functionality in the Client API (JavaScript)
I will warn you, the woman speaking has probably the most monotone voice I have ever heard, which is a shame because the information is very useful but it sometimes become very difficult to hear it because I was tuning out.
She explains new functions at around 10 minutes with some examples
if you want to see what code has changed then this post lays it out really well
http://blog.sonomapartners.com/2013/09/crm-2013-new-client-api-methods.html
it has thing like this
Entity
- Xrm.Page.data.entity.getPrimaryAttributeValue()
- Returns a string value of the primary attribute for the entity
UI
- Xrm.Page.ui.setFormNotification()
- Takes in a string value to set a form notification with the passed in string
- Pass in “ERROR”, “INFORMATION” or “WARNING” to dictate the type of notification