Google Adsense Error “TagError: adsbygoogle.push() error: No slot size for availableWidth=0 “

I used:

window.onload = function() {
    
}

My site was loading pages in a special way, making heavy use of AJAX, so it had to be this way. Hope this helps someone.

EDIT 2018: I feel like I should mention now that the preferred way to do this would be with window.addEventListener( 'load', ... ), instead of the old method of window.onload = ...