<pre class="line-numbers language-csharp">
  <code>
    //高亮代码
  </code>
</pre>

....

highlightAll: function(async, callback) {

  //var elements = document.querySelectorAll('code[class*="language-"], [class*="language-"] code, code[class*="lang-"], [class*="lang-"] code');
  //for (var i=0, element; element = elements[i++];) {
  //  _.highlightElement(element, async === true, callback);
  //}
    
  //支持 PRE 标签，修改为
  var clsReg = /\s*\blanguage-\b\s*/;
  var pres = document.querySelectorAll("pre");
  for (var i = 0, pre; pre = pres[i++];) {
    var isCode = false;
    if ((pre.firstChild 
    && (isCode = (pre.firstChild.tagName === "CODE")) 
    && clsReg.test(pre.firstChild.className)) 
    || clsReg.test(pre.className)) {
      if (!isCode) pre.innerHTML = "<code>" + pre.innerHTML + "</code>";
      _.highlightElement(pre.firstChild, async === true, callback);
    }
   }
}

....