pat-content-mirror

A pattern that provides rich dynamic functionality to a textarea. It is used for comments in the social stream.

The main functionality is provided by maintaining a "mirror" element that is updated every time the main textarea is changed. This element, which can be specified using a CSS selector in the target option, sits behind the textarea, and allows us to overcome the limitations of text-only content in the html textarea element. The user interacts with the textarea, mostly by typing, and the .content-mirror reflects the textarea content, but can also contain links to other users or tags.

The pattern would typically be applied to a textarea element, though it is not required. In addition, another element must be present to act as the content mirror.
When the designated content mirror is empty, the pattern injects a placeholder element (<em class="placeholder">Leave a comment</em>).

By default, the pattern looks for the content mirror using the CSS selector p.content-mirror .text, though this can be overridden by the target option.

The placeholder can be overridden by the placeholder option.

The example html below shows a structure that would work with the defaults:

<p class="content-mirror"
    ><span class="text"
    ><em class="placeholder">Leave a comment</em></span
    ></p>
<textarea placeholder="Leave a comment" class="pat-content-mirror"></textarea>