+++ title = "Code blocks" weight = 1 +++ Markdown already supports code samples both inline (using single backticks like \`some code here\`) and in blocks. **Infusion** will syntax highlight HTML, CSS, and JavaScript if you provide the correct language in the formulation of the block. So, this… {{}} ```html <button aria-pressed="false">toggle me</button> ``` {{}} … will result in this: ```html ``` Note that the syntax highlighting uses a greyscale theme. **Infusion** is careful not to use color as part of its own design, because these colors may clash with those of the design being illustrated and discussed. {{% note %}} To preserve the wrapping inside code blocks, horizontal scrolling is implemented. To make sure scrolling is keyboard accessible, code blocks are focusable. An `aria-label` is provided to identify the code block to screen reader users. {{% /note %}} ## Annotated code **Infusion** offers the ability to highlight and annotate specific parts of your code examples using the `code` shortcode. Take an accessible dialog. You may wish to point out key attributes that make that dialog support assistive technologies: {{}}

Confirmation

Press Okay to confirm or Cancel

{{}} You mark out the highlighted areas using triple square brackets like so: {{}} {{<code>}} <div [[[role="dialog"]]] [[[aria-labelledby="dialog-heading"]]]> <button [[[aria-label="close"]]]>x</button> <h2 [[[id="dialog-heading"]]]>Confirmation</h2> <p>Press Okay to confirm or Cancel</p> <button>Okay</button> <button>Cancel</button> </div> {{</code>}} {{}} Better still, if you include `numbered="true"`, each highlight is enumerated so you can reference it directly in the ensuing text. If you follow the shortcode directly with an ordered list, the styles match: {{

}}

  
  Confirmation
  Press Okay to confirm or Cancel
  
  

{{

}} 1. The dialog is only announced as a dialog if it takes the `dialog` ARIA role 2. The `aria-labelledby` relationship attribute makes the element carrying the `id` it points to its label 3. The close button uses `aria-label` to provide the text label "close", overriding the text content 4. The heading is used as the dialog's label. The `aria-labelledby` attribute points to its `id` You just include `numbered="true"` on the opening shortcode tag: {{}} {{<code numbered="true">}} <div [[[role="dialog"]]] [[[aria-labelledby="dialog-heading"]]]> <button [[[aria-label="close"]]]>x</button> <h2 [[[id="dialog-heading"]]]>Confirmation</h2> <p>Press Okay to confirm or Cancel</p> <button>Okay</button> <button>Cancel</button> </div> {{</code>}} 1. The dialog is only announced as a dialog if it takes the `dialog` ARIA role 2. The `aria-labelledby` relationship attribute makes the element carrying the `id` it points to its label 3. The close button uses `aria-label` to provide the text label "close", overriding the text content 4. The heading is used as the dialog's label. The `aria-labelledby` attribute points to its `id` {{}} ### JavaScript example {{

}}
/* Enable scrolling by keyboard of code samples */
(function () {
  var codeBlocks = document.querySelectorAll('pre, .code-annotated');

  Array.prototype.forEach.call(codeBlocks, function (block) {
    if (block.querySelector('code')) {
      block.setAttribute([[['role', 'region']]]);
      block.setAttribute([[['aria-label', 'code sample']]]);
      if (block.scrollWidth > block.clientWidth) {
        block.setAttribute('tabindex', '0');
      }
    }
  });
}());
{{

}} 1. The `region` role announces the block as a region 2. The `aria-label` describes the kind of content to be expected in the region {{% note %}} As you may have noticed, using specified highlights with the `code` shortcode sacrifices syntax highlighting. If you want syntax highlighting you must use the markdown triple back-tick syntax and annotation is not available. {{% /note %}}