<!DOCTYPE html> <html class="reftest-wait"> <head> <style type="text/css"> #table1 { display: table; height: 20px; width: 100px; background-color: green; margin-bottom: 20px; } #table2 { display: none; height: 20px; width: 100px; background-color: red; margin-top: 20px; margin-bottom: 20px; } #table3 { display: table; height: 20px; width: 100px; background-color: blue; margin-top: 20px; } </style> <script type="text/javascript"> function test() { document.getElementById('table2').style.display = 'table'; document.documentElement.removeAttribute('class'); } document.addEventListener('MozReftestInvalidate', test, false); </script> </head> <body> <div id="table1"></div> <div id="table2"></div> <div id="table3"></div> </body> </html>