Works for me in CS:S. Although there's a glitch when it closes instantly, so you have to type "page" command two times. It doesn't happen if VGUIMenu is sent by popup, though, or by other matters.
Oh, and in CS:GO you won't get HTML MoTD to work that easy. You'll need to use a hack like this:
Syntax: Select all
var popup=window.open("https://google.com/", "MOTD", "scrollbars=yes");
Host this page on your personal web-server and open it in your VGUIMenu instead of http://google.com/