LayoutTests/perf/set-attribute.html

<script src="../resources/magnitude-perf.js"></script>
<script>
var key = 'counter';

function setupFunction(magnitude)
{
    element = document.createElement('div');
    counter = 0;
}

function test(magnitude)
{
    element.setAttribute(key, counter ? counter-- : counter++);
}

Magnitude.description("Tests that setAttribute is constant time.");
Magnitude.run(setupFunction, test, Magnitude.CONSTANT);
</script>
</body>