> For the complete documentation index, see [llms.txt](https://learn.us-themes.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://learn.us-themes.com/week-4/day-18.md).

# Day 18

### Custom JS code (1h)

* Custom Code in Theme Options
  * Learn where exactly the Custom JS code added via the Theme Options > Custom Code tab is output by adding some code there and inspecting the source of the front page.
  * Add JS code that will alert any message to Theme Options > Custom Code > Code before \</head> field.
  * Add JS code that will change the body background color to Theme Options > Custom Code > Code before \</body> field. Use the jQuery library.
* Custom JS code for a particular Page/Post
  * Add JS code that will change font (size/color/etc) to your liking either for the whole page or to some particular element. Do **not** use the jQuery library.

### Send the report

Send the summary and link to the results to the curator.