Converting a Website Into a Single Page App
It will work, but consider why you might be doing SPA's:


No more full screen flickering, better user experience
Keep your state on the browser side instead of pingponging it between server &amp; browser
Less network traffic if you only request for data &amp; do the rendering with templates in JS


With your approach, 


You are rebuilding the whole DOM from scratch everytime, so there will still be flickering.
With script tags being replaced while JS is still running, I dont even want to think about what mess your state will be in ;)
You are still fetching data + layout from the server, so not gaining anything from a network perspective.


Furthermore, you run the risk of memory leaks, which happen like this:


Add any listener to your DOM
Forget to unbind that listener when the user clicks a link
New content is loaded, old DOM is gone, but that old listener is still out there