How to bind menu items in to a label

Question

I had master page it containt
menu
lable
four buttons

then i had child page for respective master page on that i had

gridview and some pop up menu's

i need to change the label according to menu content when i click on menu items

eg in master menu i have sub menu

designation
employee
Emplpoyee Details

when i clicj on designation sub menu i want to change the label in to designation and when i click employee i want to change the label in to employee.