# Javascript

CSS variables can be accessed and updated in JavaScript, which allows you to accomplish things that were previously very complicated, like dynamically applying style themes. By updating a few key variables based on user input, you can reskin an entire interface.

Update CSS variables in JS by using the `setProperty` method on the document root’s style property.

```javascript
document.documentElement.style.setProperty(`--color-primary`, `#4299e1`);
```

You can also alias variables to other variables, this is useful for using a consistent property throughout your codebase that can be dynamically updated without losing meaning.

```javascript
function enableDarkMode() {
  document.documentElement.style.setProperty(`--color-background`, `var(--color-black)`);
  document.documentElement.style.setProperty(`--color-text`, `white`)
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://www.pollen.style/basics/javascript.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.