<link /> tag. The Less stylesheet along with the compiler looks like this:
<link rel="stylesheet/less" type="text/css" href="main.less" /> <script src="//cdnjs.cloudflare.com/ajax/libs/less.js/2.5.1/less.min.js"></script>
Note: Compiling Less in the client-side (or in the browser) is generally not recommended. It should used only for development or when using dynamic settings that make it not possible to compile server-side.