<html><head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <script> function load() { function next() { if (count < 5) iframe.src = 'data:text/html;charset=utf-8,iframe ' + (++count); } var count = 0; var iframe = document.createElement('iframe'); iframe.onload = function () { setTimeout(next, 0) }; document.body.appendChild(iframe); setTimeout(next, 0); } </script> </head> <body onload="load()"> Testcase </body> </html>