---
title: Operating Environment
---

# Operating Environment

Requirements for operating systems:

- iOS 11.0 or later
- Android 5.0 or later, with a browser kernel 54.0.0 or later

## JavaScript engine

JavaScript programming for Smart MiniApp consists of the logic layer and SJS scripts. The programming code runs through different threads on the same JavaScript engine.

The JavaScript engine varies, depending on different operating systems. For iOS, the scripts run on the JavaScriptCore engine provided by the operating system. For Android, the scripts run the V
8 engine provided by mobile apps.

The container operating environment currently supports ECMAScript 6 (ES6) syntax that you can apply to your project with ease.

### Execution environment

All JavaScript programs of Smart MiniApp run in [strict mode](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode).

## Limits on scripts

For security purposes, Smart MiniApp has limits on certain ES syntax and APIs.

1. Prohibited to access the `global` object `globalThis`.
2. Prohibited to access the `window` `document` object and the methods and properties of the object.
3. Prohibited to use `Function` `eval` to dynamically run code.