<!DOCTYPE HTML> <html> <head> <!-- Test appends --> <style> body > div { border:1px solid black; margin:1em; font-family:sans-serif; letter-spacing:2px; } #d2:after { content:"Kitty"; } #d3:after { content:"ty"; } </style> <script>function flush() { document.body.offsetHeight; }</script> </head> <body> <div id="d1"><span>Hello</span> <script>flush();</script><span>Kitty</span></div> <div id="d2"><script>flush();</script><span>Hello</span> </div> <div id="d3"><span>Hello</span> <script>flush();</script><span>Kit</span></div> <div id="d4"><span>Hello</span><script>flush();</script> <span>Kitty</span></div> </body> </html>