For slow loading using client side includes with JS to load non-core pieces of the page is a pretty common perceptual speed up technique- if the main content lo

For slow loading using client side includes with JS to load non-core pieces of the page is a pretty common perceptual speed up technique- if the main content loads quickly, we can wait for the shared elements to render. Client side includes didn't make it into HTML5. Maybe in HTML6? Check this space in 2020. http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2008-August/015792.html http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2008-Aug...