now i need some help with my jump timer

ok it will go up ok and stop when the Millisecs() >= jumptime but i can't get it to come back down...it all looks ok to me but i guess it's not

If KeyHit(57) 
jumptime = MilliSecs() + 2000
	If MilliSecs() < jumptime
	yvel# = yvel# + 2 
		If MilliSecs() >= jumptime
		yvel# = yvel# - 2
			If yvel# = 0 
				yvel# = 0
			EndIf
	 	EndIf
	EndIf 
EndIf