NOTE: If you want to use GitHub language colors, consider using @mikazuki/language-colors instead of this.
Bootstrap-Style Badges of GitHub colors for all the programming languages.
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8>
<link href="/path/to/language-badge.css" rel="stylesheet">
</head>
<body>
<span class="badge badge-javascript">JavaScript</span>
</body>
</html>All badges can be seen here.