<!DOCTYPE html> <html class="reftest-wait"> <head> <style> #a:first-child::first-line { } </style> <script> function runTest() { document.getElementById("a").removeAttribute('style'); document.body.offsetWidth; document.documentElement.className = ""; } </script> </head><body onload="runTest()"> <div style="position:absolute;"> <span id="a" style="position:fixed;"> <span> <span style="display:table;position:absolute;"> </span> </span> Loading this should not crash Mozilla </span> </div> </body></html>