web3.js/docs/getting-started.rst

===============
Getting Started
===============

The web3.js library is a collection of modules which contain specific functionality for the ethereum ecosystem.

- The ``web3-eth`` is for the ethereum blockchain and smart contracts
- The ``web3-shh`` is for the whisper protocol to communicate p2p and broadcast
- The ``web3-bzz`` is for the swarm protocol, the decentralized file storage

The following page will describe how to install and add web3.js to your project.
You can find some extra examples in the :ref:`API-reference <api-reference>` and the `examples here <https://github.com/ethereum/web3.js/tree/master/examples>`_.

Please also check out these `useful patterns <https://github.com/ethereum/wiki/wiki/Useful-Ðapp-Patterns>`_ for building Ðapp.


.. _adding-web3:

Adding web3.js
==============

.. index:: npm
.. index:: bower
.. index:: meteor

First you need to get web3.js into your project. This can be done using the following methods:

- npm: ``npm install web3``
- bower: ``bower install web3``
- meteor: ``meteor add ethereum:web3``
- pure js: link the ``dist/web3.min.js``

After that you need to create a web3 instance and set a provider.
Ethereum supported Browsers like Mist or MetaMask will have a ``ethereumProvider`` available, web3.js is setting this one to ``Web3.givenProvider``.
If this property is ``null`` you need to connect to a remote/local node.

.. code-block:: javascript

    // in node.js use: var Web3 = require('web3');

    var web3 = new Web3(Web3.givenProvider || new Web3.providers.WebsocketProvider("ws://localhost:8546"));

Thats it! now you can use the ``web3`` object.