<html class="reftest-wait"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> </head> <body onload="start()"> <iframe src="data:text/html,<body contenteditable spellcheck=false>foo bar"></iframe> <script> function start() { var iframe = document.querySelector("iframe"); var win = iframe.contentWindow; var doc = iframe.contentDocument; setTimeout(function() { doc.body.focus(); // Now try to set the caret without moving it win.getSelection().collapse(doc.body.firstChild, 1); document.documentElement.removeAttribute("class"); }, 0); } </script> </body> </html>