third_party/blink/web_tests/fast/css/first-letter-replace-text.html - chromium/src - Git at Google

 <!doctype HTML>
 <style>
 p:first-letter {
   float: left;
   color: green;
 }
 </style>
 <p id="replace">Lorem ipsum</p>
 <script>
   document.body.offsetTop; // Force layout.
   var el = document.getElementById("replace");
   el.firstChild.data = el.firstChild.data.replace(/[aeiu]/g, "o");
 </script>
	<!doctype HTML>
	<style>
	p:first-letter {
	float: left;
	color: green;
	}
	</style>
	<p id="replace">Lorem ipsum</p>
	<script>
	document.body.offsetTop; // Force layout.
	var el = document.getElementById("replace");
	el.firstChild.data = el.firstChild.data.replace(/[aeiu]/g, "o");
	</script>