<!DOCTYPE html> <html> <body> <style> #foo { overflow: scroll; height: 100px; } </style> <div id="foo"> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> Mozilla Firefox<br> <script> foo.createShadowRoot().innerHTML = "<content></content>"; </script> </body> </html>