resolve DNS when browser is idled.
<link rel="dns-prefetch" href="http://www.example.com">
You can also control(opt in / our) prefetch by using meta tag
<meta http-equiv="x-dns-prefetch-control" content="on">
preload contents when current page is loaded fully.
<link rel="prefetch" href="http://www.example.com/hoge.png">
<link rel="prefetch" href="http://www.example.com/">
This is supported in Google Chrome.
<link rel="subresource" href="jquery.js">
Chronium project says that…
“LINK rel=subresource” provides a new link relation type with different semantics from LINK rel=prefetch. While rel=prefetch provides a low-priority download of resources to be used on subsequent pages, rel=subresource enables early loading of resources within the current page. Because the resource is intended for use within the current page, it must be loaded at high priority in order to be useful.
Currently prerendering tag is only supported in Google Chrome.
<link rel="prerender" href="http://www.example.com/">
Prerendering may make your site slowly. so you had better define height relative page ( e.g. next page).