本地引入web3

> web3
Thrown:
ReferenceError: web3 is not defined
> var Web3=require('web3')
undefined
> Web3
[Function: Web3] {
  providers: {
    HttpProvider: [Function: HttpProvider],
    IpcProvider: [Function: IpcProvider]
  }
}
> var web3=new Web3(new Web3.provider.HttpProvider('http://localhost:8206'))
Thrown:
TypeError: Cannot read property 'HttpProvider' of undefined
> var web3=new Web3(new Web3.providers.HttpProvider('http://localhost:8206'))
undefined
> web3
Web3 {
  _requestManager: RequestManager {
    provider: HttpProvider {
      host: 'http://localhost:8206',
      timeout: 0,