The name of the JavaScript function can be user defined or native. For example, to specify that the native function alert should be called, this property could be set to "alert('hello')." To specify that a user-defined function, myFunction, should be called, this property would be set to "myFunction."
A user-defined function must be defined either inline or in a linked JavaScript (.JS) file and can accept the following parameters:
Object. The CSOM toolbar object calling the function.
Object. The CSOM object of the button that was clicked.
Object. The CSOM event object.
The parameters above are optional and can be named as desired.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2