<main id="a">
<section class="a">
<p class="b c"></p>
<p class="b c"></p>
<a class="d" href="#b"></a>
</section>
</main>
<style>
.f {}
.a {}
.a {}
</style>
<script>
a = document.querySelector('.a');
b = document.querySelector('.e');
c.className = 'a';
d = document.querySelector('#foo');
</script>