'字符串转换成二进制
function StrToBin(str)
    dim curChr, curAsc, low, high
    dim i
    for i=1 To Len(str)
        curChr = Mid(str, i, 1)
        curAsc = Asc(curChr)
        'asc对中文字符求出来的值可能为负数，
        '加上65536就可求出它的无符号数值
        '-1在机器内是用补码表示的0xffff,
        '其无符号值为65535,65535=-1+65536
        '其他负数依次类推。
        if curAsc < 0 then
            curAsc = curAsc + 65535
        end if
        '对中文的处理：把双字节低位和高位分开
        if curAsc > 255 then
            low = Left(Hex(Asc(curChr)), 2)
            high = Right(Hex(Asc(curChr)), 2)
            StrToBin = StrToBin & ChrB("&H" & low) & ChrB("&H" & high)
        else
            StrToBin = StrToBin & ChrB(AscB(CurChr))
        end If
    next
end function