URL querystrings and hash parameters

`location.search` and `location.hash` are now available for use in your notebooks (by being passed down from the parent frame). For example, click [this link](?one=1&two=2) to add a querystring to this notebook’s URL.

The value of `location.search` is: ```

And we can use the normal `hashchange` event to respond to changes in `location.hash`, which is currently: ``.

const hash = Generators.observe(notify => {
  const hashchange = () => notify(location.hash);
  hashchange();
  addEventListener("hashchange", hashchange);
  return () => removeEventListener("hashchange", hashchange);
})

This is Markdown with some simple hashful links:

• #simple
• #hashful
• #links`

In general, you can use \`document.baseURI\` from within a notebook to get the browser’s current URL:

```js echo
document.baseURI