> ## Documentation Index
> Fetch the complete documentation index at: https://docs.darvas.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Quickstart

> Render your first custom indicator on a Darvas chart in 5 minutes.

## 1. Open the indicator editor

In Darvas, open `/terminal`, click **Add indicator** in the chart sidebar, and select **Custom indicator**. The script editor opens with a default template.

## 2. Paste this script

```js theme={null}
const len = input.int("Length", 14);
const src = input.source("Source", "close");

plot("MA", null, { color: "#22c55eFF", linewidth: 2 });
plot("Diff", null, { color: "#a78bfaFF", style: "histogram" });

onBar(() => {
  const ma = ta.sma(src, len);
  plot("MA", ma);
  plot("Diff", ctx.close() - ma);
});
```

## 3. Click "Add to chart"

The script runs against the visible bars. You will see two new series on your chart pane: a moving average overlay (`MA`) and a histogram of the close-minus-MA distance (`Diff`).

## 4. Iterate

Edit the script, change `len` from `14` to `50`, click **Add to chart** again. The chart redraws with the new parameter. Your draft lives in the browser until you save it.

## Anatomy of the script

```js theme={null}
// Top-level: runs ONCE when the script is loaded.
const len = input.int("Length", 14);    // user-tweakable parameter
plot("MA", null, { color: "#22c55eFF" }); // declare a series and its style

// onBar: runs ONCE PER BAR. This is where computation happens.
onBar(() => {
  const ma = ta.sma(src, len);   // compute SMA at this bar
  plot("MA", ma);                // emit the value for this bar
});
```

Top-level state (the `const`s above) persists across bars via JavaScript closures. `onBar` reads them on every bar.

<Note>
  Top-level code runs **once**. `onBar` runs **per bar**. If you compute something in the top-level body that depends on `ctx.close()`, it will be the close at script-init time (usually the first bar) - almost never what you want. Put per-bar logic inside `onBar`.
</Note>

## Where to next

<CardGroup cols={2}>
  <Card title="Editor walkthrough" icon="window" href="/editor-walkthrough">
    Tour the script editor and inputs panel.
  </Card>

  <Card title="Plot styles" icon="chart-bar" href="/plotting/plot-styles">
    Histogram, area, arrows, circles, and more.
  </Card>

  <Card title="Drawing entities" icon="pen-ruler" href="/entities/overview">
    Persistent S/R lines, FVG boxes, order blocks.
  </Card>

  <Card title="Series and history" icon="chart-area" href="/essentials/series">
    Access prior-bar values like Pine's `x[1]`.
  </Card>
</CardGroup>