With recent nightly builds, elements having position:fixed have a null offsetParent property. The following snippet should return the body node : <!doctype html> <html> <body onload="alert(document.getElementById('hop').offsetParent);"> <div id="hop" style="position:fixed">Test</div> </body> </html>
This bug depends on bug 19149 . One of them is invalid.
According to W3C specs[1], this is correct behavior. This is actually a progression, not a regression, if the spec is treated as canon. [1] http://www.w3.org/TR/cssom-view/#offset-attributes