[Bug-wget] wget --spider doesn't get file size

[Yiwei Yang]

I want to get some file size. Some people recommend wget --spider. However,
when I run it on some links, like http://autos.cn.yahoo.com/,
http://www.cbsa.gc.ca/menu-eng.html,http://oprofile.sourceforge.net/mail/and
so on,  then it said Length: unspecified [text/html]. Is there way to
solve this or I could use another way to get file size? Thank you!