<!DOCTYPE HTML>
<html>
<head>
<script>
if (window.testRunner)
    testRunner.dumpAsText();

window.onload = function() {
    var elmt = document.getElementById("probe");  
    var color = window.getComputedStyle(elmt, null).getPropertyValue("background-color");  
    document.getElementById("results").innerHTML= color;
}
</script>
<style>
@charset "utf-8";
.green {
  background-color: green;
}
</style>
</head>
<body>
<div id="probe" class="green">
I should have a green background.
</div>
<div id="results"></div>
</html>