There were a few bugs with our new heatmaps for people who were putting our tracking code in their HTML head tag, and there were an alarmingly large number of you doing so. Those bugs are fixed now, but that’s beside the point of this little post.
The only valid exception here is if it’s hosted by a major provider such as Google, and you rely on the functionality of that code as the page loads (which we do for Google’s map API, but that’s it). That is the only exception.
So… if you’ve got our code in your HTML head, please move it instead to the bottom of your HTML, right before the closing /body tag, as has always been recommended on the page where you grab your tracking code from.
Bonus pro-tip: For first party elements, your CSS file should always be the very first item in your HTML head. That way your site will always look “proper” as soon as possible, beacuse this will be the very first thing the browser downloads after the HTML itself.