Uses Sass.js to allow direct embedding of Sass and Scss in HTML (like less.js)

sass.link.js

// NOTE: Requires sass.js (https://github.com/medialize/sass.js/)
function setupSass(el) {
  const url = el.getAttribute('href');
  let xmlhttp;
  if (window.XMLHttpRequest) {
    // code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp = new XMLHttpRequest();
  } else {
    // code for IE6, IE5
    xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
  }
  xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState === 4 && xmlhttp.status === 200) {
      const css = Sass.compile(xmlhttp.responseText);
      let style = document.createElement('style');
      style.innerHTML = css;
      el.parentNode.replaceChild(style, el);
    }
  }
  xmlhttp.open('GET', url, true);
  xmlhttp.send();
}

const sass = document.querySelectorAll('[rel="stylesheet/scss"], [rel="stylesheet/sass"]');
for (let el of sass) {
  setupSass(el);
}