<style>
#test1 { -webkit-background-composite: highlight; }
#test2 { -webkit-background-composite: invalid; }
</style>
Tests that highlight is treated the same as an invalid value for a composite operation:<br>
<div id="result"></div>
<span id="test1"></span>
<span id="test2"></span>
<script>
value1 = window.getComputedStyle(document.getElementById('test1')).webkitBackgroundComposite;
value2 = window.getComputedStyle(document.getElementById('test2')).webkitBackgroundComposite;
result.innerText = value1 === value2 ? "PASS" : "FAIL";
if (window.testRunner)
    testRunner.dumpAsText();
</script>