NOTE: This also works for domains, not just sub-domains.
What you are doing is creating a Meta Tag Redirect.
The code looks something like this.
<meta content=”0; url=html://www.the-redirect-page.com” http-equiv=”refresh” />
Content=”0 the 0 is the time in seconds to make the redirect goes to the page is in the url=html://www.the-redirect-page.com” Change the www.the-redrect-page.com to the page you want it to be automatically redirected to.
This code goes between the….tags in the header of the html code.