code: function _getLanguageForBlock(block) {
  
          // if this doesn't have a language but the parent does then use that
          // this means if for example you have: <pre data-language="php">
          // with a bunch of <code> blocks inside then you do not have
          // to specify the language for each block
          var language = _attr(block, 'data-language') || _attr(block.parentNode, 'data-language');
  
          // this adds support for specifying language via a css class
          // you can use the Google Code Prettify style: <pre class="lang-php">
          // or the HTML5 style: <pre><code class="language-php">
          if (!language) {
              var pattern = /\blang(?:uage)?-(\w+)/,
                  match = block.className.match(pattern) || block.parentNode.className.match(pattern);
  
              if (match) {
                  language = match[1];
              }
          }
  
          return language;
      }
docs: gets the language for this block of code
  
  @param {Element} block
  @returns {string|null}