Revisiting the Float Label pattern with CSS — That Emil is Emil Björklund
A clever technique by Emil to implement the “float label” pattern using CSS. It all hinges on browsers supporting the :placeholder-shown pseudo-class which, alas, is not universal.
I was hoping that maybe @supports could come to the rescue (so that a better fallback could be crafted), but that tests for properties and values, not selectors. Damn!