<!DOCTYPE html>
<html>
<head>
<script type = "text/javascript" src = "https://d3js.org/d3.v4.min.js"></script>
</head>
<body>
<div class = "myclass">
Hello World!
</div>
<script>
d3.select(".myclass").attr("style", "color: red");
</script>
</body>
</html>