如何判断发言是否为空？

if len(usersays)<>0 then 
session("whoto")=request.form("whoto") 
session("action")=request.form("action") 
if instr(usersays,chr(39))>0 then 
usersays=replace(usersays,chr(39),"/"&chr(39)) 
end if 
if instr(usersays,chr(34))>0 then 
usersays=replace(usersays,chr(34),"/"&chr(34)) 
end if 

application.lock 

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