browsertest.js

// Adapted from http://stackoverflow.com/questions/1895727/how-can-i-detect-the-browser-with-php-or-javascript?rq=1
// and http://docs.mathjax.org/en/latest/dynamic.html

// If browser is not Firefox, call MathJax
(function () {
  var userAgent = navigator.userAgent.toLowerCase();
  if (!/firefox/.test(userAgent)) {
    var head = document.getElementsByTagName("head")[0],
        script1, script2;

    script1 = document.createElement("script");
    script1.type = "text/x-mathjax-config";
    script1.innerHTML = "//<![CDATA[\n" +
      "MathJax.Hub.Config({\n" +
      "  'HTML-CSS': {  linebreaks: { automatic: true },\n" +
      "                 availableFonts: [], preferredFont: null, webFont: 'STIX-Web' },\n" +
      "         SVG: {  linebreaks: { automatic: true } }\n});\n" +
      "//]]>";

    script2 = document.createElement("script");
    script2.src  = "https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML";
    script2.type = "text/javascript";

    head.appendChild(script1);
    head.appendChild(script2);
  }
}());