function isInteger(para)
on error resume next
dim str
dim l,i
if isNUll(para) then
isInteger=false
exit function
End if
str=cstr(para)
if trim(str)="" then
isInteger=false
exit function
End if
l=len(str)
for i=1 to l
if mid(str,i,1)>"9" or mid(str,i,1)<"0" then
isInteger=false
exit function
End if
next
isInteger=true
if err.number<>0 then err.clear
End function