# Update field options based on previous selection

## Overview

In this example, the options in Dropdown B will be updated dynamically based on what the user selects as the value for Dropdown A. Dropdown A's options will be `Positive` and `Negative`, and Dropdown B will display positive or negative number options accordingly.

## Rule Logic

This rule should run when the value of Dropdown A is changed and when the step that Dropdown B is on is loaded.

```
if (DropdownA.value === 'Positive') DropdownB.options = ['1', '2', '3'];
else DropdownB.options = ['-1', '-2', '-3'];
```