> <http://www.w3schools.com/dom/default.asp>
> This site can not be copied by WinHttrack. It's the first 
> time that winHttrack can not do it.
> I have the version:
> WinHTTrack Website Copier 3.20RC4B

There is a robots.txt feature that, by default, prevent 
fropm downloading parts of the site.

But the real problem is that this site seems to filter 
offline browsers, including httrack (maybe due to abuses, 
like fast crawls?)
You can change the browser ID (see in the httrack options) 
to bypass that, BUT please use BANDWIDTH LIMITERS (like 
5KB/s, and 2 simultaneous connections) to limit the remote 
server load!