<!doctype html>
<head>
<title>line-box-contain: none</title>
<style>
.test { -webkit-line-box-contain: none; line-box-contain: none; font: 64px/1em Ahem; background-color:red; margin-top:1em }
.badline { color:red }
.goodline { color: green }
</style>
</head>
<body>
You should see a green line below.  If you see any red, the test has failed.

<div class="test">
<span class="badline">xxxxx</span><br>
<span class="badline">xxxxx</span><br>
<span class="badline">xxxxx</span><br>
<span class="badline">xxxxx</span><br>
<span class="goodline">xxxxx</span>
</div>