I'm new with Alfresco, and I would like to know the difference between JavaScript API and JavaScript Services API, and I hope someone provide me an example of a tuorial beginning of the creation of a model to handling this model from the JavaScript API.
As stated here Alfresco Javascript API
The Alfresco JavaScript API allows script writers to develop JavaScript (ECMA Script) 1.7 compatible files that access, modify, and create Alfresco repository objects.
This means you are able to extend and create new webscripts to interact with the Alfresco plaform. Moreover it provides some root scope objects that wrap the common Alfresco repository concepts.
Conversely Javascript services API refers to all the available methods to interact with sites, which are collaborative areas inside Alfresco share.
In addition, as an extra resource, you can find this useful Alfresco API overview that depicts all the various API and their main purpose.