<!DOCTYPE html> <html> <head> <script> window.onload = function() { document.body.offsetWidth; document.getElementById("foo").style.top = "200px"; }; </script> </head> <body style="font-size: 0"><span id="foo"><span style="position: relative; top: inherit; display: block; font-size: medium">This text should be 200px from the top of the body</span></span></body> </html>