How to apply a CSS filter to a background image

Question

Because I'm working within Backbone, I'm utilizing CSS to set a JPEG file as the background picture for a search page. contexts for js

background-image: url("whatever.jpg");

The background is the sole element to which I want to apply a CSS 3 blur filter, but I'm not sure how to style only that one element. When I try:

-webkit-filter: blur(5px);
-moz-filter: blur(5px);
-o-filter: blur(5px);
-ms-filter: blur(5px);
filter: blur(5px);

In my CSS, it styles the entire page rather than just the background, just below the background-image. Is it possible to choose just the image and use the filter on it? Or, is there a method to simply disable the blur for every other component on the page?