Tryit Editor v1.8

Source Code:

<!DOCTYPE html>
<html>
<head>
<style> 
[class^="test"]
{
background:#ffff00;
}
</style>
</head>
<body>

<div class="first_test">The first div element.</div>
<div class="second">The second div element.</div>
<div class="test">The third div element.</div>
<p class="test">This is some text in a paragraph.</p>

</body>
</html>

Result:

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