Currant is a single-threaded programming language that runs in the browser. It has simple interoperability with JavaScript and can be easily embedded into a webpage:
<!doctype html>
<html>
<head>
<script src="currant.js"></script>
<currant-script>
log("Hello, Currant!");
</currant-script>
</head>
<body>
</body>
</html>Documentation for Currant is accessible here.