function Select_Number(str_num)
  dim len_number
  dim i
  dim str1
  dim flag
  
  len_number=len(str_num) 
     flag=0
     for i=1 to len_number
        str1=mid(str_num,i,1)
        if Asc(str1)>=48 and Asc(str1)<=57 then
           flag=1                      
        else
           flag=0
           exit for   
        end if
     next   
    Select_Number=flag  
end function