Last Updated on 03/05/2020

(
	obj = modPanel.getCurrentObject()
	if obj != undefined then 
	(
		case (classof obj) of 
		(
		Edit_Poly:obj.setoperation #SelectHardEdges	
		Editable_Poly:obj.selectHardEdges()
		)
	)
	
)

Simple maxscript which allows select Hard Edges in Editable Poly object or in Edit Poly modifier in 3ds Max.