@benjamine Well :
What we need here is to activate :
"header footer section aside nav article figure figcaption hgroup time"
The String#replace trick is a way of avoiding a for loop. The /\w+/g RegExp targets words, and the second argument, the function, is executed for each word (that's the role or the "g" in the RegExp). Then we just have to create elements using document.createElement.
Putting this script at the very beginning of the page makes the whole page ready to recognize these tagNames.