# Script block

> Execute custom JavaScript code within your flow

Source: https://edesy.in/docs/zapbot/logic/script

The "Script" block allows you to execute Javascript code.

> **Note:** This block doesn't allow you to create a custom visual block

![Code block](https://edesy.in/images/zapbot/blocks/logic/code.png)

> **Note:** Variables in script are not parsed, they are evaluated. So it should be treated as if it were real javascript variables.
>
> You need to write `console.log({{My variable}})` instead of `console.log("{{My variable}}")`

## `setVariable` function

If you want to set a variable value with Javascript, the [Set variable block](https://edesy.in/docs/zapbot/logic/set-variable) is more appropriate for most cases.

However, if you'd like to set variables in a Script block, you can use the `setVariable` function in your script:

```js
if({{My variable}} === 'foo') {
  setVariable('My variable', 'bar')
} else {
  setVariable('My variable', 'other')
}
```

The `setVariable` function is only available in script executed on the server, so it won't work if the `Execute on client?` is checked.

## Limitations on scripts executed on server

Because the script is executed on a isolated and secured environment, there are some limitations.

- Global functions like `console.log`, `setTimeout`, `setInterval`, etc. are not available
- The `fetch` function behavior is slightly different from the native `fetch` function. You just have to skip the `await response.text()` or `await response.json()` part.

  ```js
  // This throws an error
  const response = await fetch('https://jsonplaceholder.typicode.com/todos/1')
  const data = await response.text()

  // This works
  const data = await fetch('https://jsonplaceholder.typicode.com/todos/1')
  ```

  `response` will always be a `string` even if the the request returns a JSON object. If you know that the response is a JSON object, you can parse it using `JSON.parse(response)`.

  ```js
  // This throws an error
  const response = await fetch('https://jsonplaceholder.typicode.com/todos/1')
  const data = await response.json()

  // This works
  const response = await fetch('https://jsonplaceholder.typicode.com/todos/1')
  const data = JSON.parse(response)
  ```

- You can't use `import` or `require` to import external libraries
- You don't have access to browser APIs like `window`, `document`, `localStorage`, etc. If you need to use browser APIs, you should check the `Execute on client?` option so that the script is executed on the user's browser.

## Examples

### Reload page

```js
window.location.reload()
```

### Redirect if a variable has a specific value

```js
if({{Category}} === 'qualified') {
  window.location.href = 'https://my-site.com'
}
```

Do you need to do something but you're not sure how to? Visit the [Zapbot community](https://edesy.in/zapbot) for help!