Images in placeholder for input fields

Since I have been doing a heap of web/html dev lately, I’ve taken to noticing things. Today, on MacWorld, I noticed this:

Google-search-placeholder

Clicking in the search box results in:

Google-search-placeholder-focus

So, there is an image in the placeholder. This is very neat!

Unfortunately, it appears this might not be a part of the HTML5 spec, but is done using JavaScript.