I've been developing this as my standard start for web pages:
<!DOCTYPE html>
<!--[if lt IE 7]> <html class="no-js lt-ie9 lt-ie8 lt-ie7"> <![endif]-->
<!--[if IE 7]> <html class="no-js lt-ie9 lt-ie8"> <![endif]-->
<!--[if IE 8]> <html class="no-js lt-ie9"> <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js"> <!--<![endif]-->
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge;" />
Unfortunately, Marketo outputs something completely different:
<!DOCTYPE html>
<html class="no-js"><!--<![endif]--><head>
<script type="text/javascript">
var mktoPreFillFields = { ... } /* an array of prefill data */
</script>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge;" />