When you call jQuery.css("styleName"), there's some chance that jQuery might return the computed style which would be returned from the window.getComputedStyle(domElement) call. However, for various styles such as width and height, jQuery instead calls a 'hook' method, like the one defined in cssHooks["width"]. The trouble is that these hooks aren't always desirable; with IE's sub-pixel rounding, for example, I want to get a computed width for an element which looks like "26.65px" and instead jQuery gives me "25px". Maybe jQuery's way is useful for something, but jQuery should provide a way to always get the computed style, as returned by the browser.