I just [answered](https://stackoverflow.com/a/26086204/3764814) a question about a JavaScript issue, and wanted to provide a runnable snippet with a complete demo based on the asker's code.

The problem lies in the fact that the CSS is irrelevant to the answer, and the HTML is just copy-pasted from the question in order to get a runnable demo.  

The HTML is much longer than the JS code I provided. In the end, it only clutters the answer.

I'd like to be able to selectively hide a part of a snippet in this situation, maybe using syntax like this:

```
<!-- language: lang-html hide: true -->

```

I know I could just hide the whole snippet and copy/paste the JS code above it in a separate block, but I believe in the [DRY principle](http://en.wikipedia.org/wiki/Don%27t_repeat_yourself).