I am trying to change the background image whenever the document is loaded, and when it hits this point: document.body.style.backgroundImage="url('../images/mobile-bckground.png')"; The page simply makes the background plain white. It is displayed like this in my javascript: $(function() { document.body.style.backgroundImage="url('../images/mobile-bckground.png')"; }); I have verified the image is in the right location, why is it doing this?