Is it possible to hide vanilla buttons (in my case crm save button), according to Javascript function or field change in Dynamics - Crm 2016 using workbench? If it's optional where can I had the connection to my display rule?
You need to add a ribbon display rule.
Control when ribbon elements are displayed
By defining display rules in rule definitions, you can use the same display rule for many command definitions. When more than one display rule is defined for a command definition, all of the display rules must evaluate as true for the ribbon element to be displayed.
This is easier using Ribbon Workbench. This article is similiar but for enable rules. In later versions of CRM disabling a button usually hides it as well.