# Knockout

**Knockout** is a JavaScript [MVVM](https://en.wikipedia.org/wiki/Model_View_ViewModel) (a modern variant of MVC) library that makes it easier to create rich, desktop-like user interfaces with JavaScript and HTML. It uses *observers* to make your UI automatically stay in sync with an underlying data model, along with a powerful and extensible set of *declarative bindings* to enable productive development.

## Getting started

[![Join the chat at https://gitter.im/knockout/knockout](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/knockout/knockout?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)

**Totally new to Knockout?** The most fun place to start is the [online interactive tutorials](https://learn.knockoutjs.com/).

For more details, see

* Documentation on [the project's website](https://knockoutjs.com/documentation/introduction.html)
* Online examples at [http://knockoutjs.com/examples/](https://knockoutjs.com/examples/)

## Downloading Knockout

You can [download released versions of Knockout](https://knockoutjs.com/downloads/) from the project's website.

For Node.js developers, Knockout is also available from [npm](https://npmjs.org/) - just run `npm install knockout`.

## Building Knockout from sources

If you prefer to build the library yourself:

1. **Clone the repo from GitHub**

   ```sh
   git clone https://github.com/knockout/knockout.git
   cd knockout
   ```

2. **Acquire build dependencies.**

   Make sure you have [Node.js](https://nodejs.org/) and [Java](https://www.java.com/en/) installed on your workstation. These are only needed to _build_ Knockout from sources. Knockout itself has no dependency on Node.js or Java once it is built (it works with any server technology or none). Now run:

   ```sh
   npm install
   ```

3. **Run the build tool**

   ```sh
   npm run grunt
   ```

   Now you'll find the built files in `build/output/`.

   To run a single task, use `--`

   ```sh
   npm run grunt -- build:debug
   ```

## Running the tests

```sh
npm test              # All tests (Node.js + headless Chrome)
npm run test:node     # Node.js non-DOM specs only
npm run test:browser  # Headless Chrome specs only
npm run grunt         # Build and test against production output
```

For interactive debugging, open `spec/runner.html` in your browser.

## License

MIT license - [https://www.opensource.org/licenses/mit-license.php](https://www.opensource.org/licenses/mit-license.php)