Use a .htaccess file for redirection. JS redirection is frowned upon by just about everyone, including visitors who dont like feeling their browser is being hijacked.
To redirect a certain page add this to your .htaccess file;
Redirect 301 /oldpage.html http://www.yoursite.com/newpage.html
(Dont forget to make your own edits)
To redirect your entire site add this line;
Redirect 301 / http://www.new-site.com/
Making the necessary edits of course.
Hope this helps.