content: import React, { Component } from 'react';
  import { render } from 'react-dom';
  
  import './index.css';
  import App from './App';
  import TitleBar from './title-bar/TitleBar';
  import SignUp from './sign/SignUp';
  import SignIn from './sign/SignIn';
  import Comment from './comment/CommentPanel';
  
  import { HashRouter, Router, Route, hashHistory } from 'react-router-dom'
  
  
  // 配置路由 (Provider 是一个react组件，提供一个全局的store使得所有的组件都可以使用)
  render((
      <div>
          <HashRouter>
              <div>
                  <Route exact path="/" component={App} />
                  <Route path="/signup" component={SignUp} />
                  <Route path="/signin" component={SignIn} />
                  <Route path="/comment" component={Comment} />
              </div>
          </HashRouter>
      </div>
  ),document.getElementById('title-bar'));