Replying Salaam to the Imam after he takes his place on the Mimbar
Question

                When the Imam gets on the minbar for the Khutbah as gives the salaam, do 
the people reply of keep silent for fear of losing the reward of the Jumu'ah 
khutbah?
Jazakumullahu Khayran
As salaamu 'alaykum
Praise be to Allah.al-hamdu lillaah.
If the Imam ascends the mimbar and greets the audience with the salaam then the 
audience should respond. This would not be considered frivolous discourse and would 
not violate the silence required for listening because the actual khutbah has not yet 
begun. Therefore, until then, the audience can recite praises of Allaah and duaa, and 
also repeat after the muathin who calls for prayer, which is timed after the Imam has 
actually greeted the audience and has taken his place on the mimbar.