SP.WebParts.WebPart.subtitle property (sp.js)
Gets a value that specifies a string that is concatenated with the title property value to form a complete title for a Web Part.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value =SP.WebParts.WebPart.get_subtitle()
Return value
Returns a String instance representing the string that is concatenated with the Title property value to form a complete title for a Web Part.
Remarks
The default value is an empty string ("").