replace <code>$math$</code> with <code>\(math\)</code>, so that we do…

… not really need to configure MathJax!

layouts/partials/footer_mathjax.html

@@ -1,12 +1,4 @@
 {{ if and (not .Params.disable_mathjax) (or (in (string .Content) "\\") (in (string .Content) "$")) }}
 <script src="{{ "/js/math-code.js" | relURL }}"></script>
-<script type="text/x-mathjax-config">
-MathJax.Hub.Config({
-  tex2jax: {
-    inlineMath: [['$','$'], ['\\(','\\)']],
-    processEscapes: true
-  }
-});
-</script>
 <script async src="{{ .Site.Params.MathJaxCDN | default "//cdn.bootcss.com" }}/mathjax/{{ .Site.Params.MathJaxVersion | default "2.7.1" }}/MathJax.js?config=TeX-MML-AM_CHTML"></script>
 {{ end }}

static/js/math-code.js

@@ -4,6 +4,10 @@
     code = codes[i];
     if (code.parentNode.tagName !== 'PRE' && code.childElementCount === 0) {
       text = code.textContent;
+      if (/^\$[^$](.|\s)+[^$]\$$/.test(text)) {
+        text = text.replace(/^\$/, '\\(').replace(/\$$/, '\\)');
+        code.textContent = text;
+      }
       if (/^\\\((.|\s)+\\\)$/.test(text) || /^\\\[(.|\s)+\\\]$/.test(text) ||
           /^\$(.|\s)+\$$/.test(text) ||
           /^\\begin\{([^}]+)\}(.|\s)+\\end\{[^}]+\}$/.test(text)) {