SP.WebParts.WebPart.zoneIndex property (sp.js)
Gets a value that specifies the index position of a Web Part within the Web Part zone.
Applies to: apps for SharePoint | SharePoint Foundation 2013 | SharePoint Server 2013
var value =SP.WebParts.WebPart.get_zoneIndex()
Return value
Returns a Int32 instance representing the index position of a Web Part within the Web Part zone.
Remarks
The value is the numerical order of a Web Part within the Web Part zone. The first Web Part in a Web Part zone must have an index value of zero.