I can do one better data:text/html,%20<x%20id=e><script>d=['','//js','/*css*/','<!--HTML-->'];for(i=4;i--;)e.innerHTML+=(i?'<textarea%20id=t'+i:'<iframe'

I can do one better data:text/html,%20<x%20id=e><script>d=['','//js','/*css*/','<!--HTML-->'];for(i=4;i--;)e.innerHTML+=(i?'<textarea%20id=t'+i:'<iframe')+'%20style=width:49%;height:48%%20oninput=\'e.lastChild.src="data:text/html;base64,"+btoa(t3[v="value"]+"<script>"+t1[v]+"<\/script><style>"+t2[v])\'>'+d[i]+'\n'</script>