<!DOCTYPE html> <html> <head> <meta http-equiv="content-type" content="text/html; charset=us-ascii"> </head> <body> <iframe width="400" height="400" src="data:application/xhtml+xml;charset=us-ascii,<html xmlns='http://www.w3.org/1999/xhtml'><h1>Test</h1></html>"></iframe> </body> </html>