webpack-dev-server无法自动刷新

Question

package.json

{
  "name": "reactstart",
  "version": "1.0.0",
  "description": "react start",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "mhyang",
  "license": "ISC",
  "dependencies": {
    "babel": "^6.23.0",
    "babel-core": "^6.24.1",
    "babel-loader": "^7.0.0",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "babelify": "^7.3.0",
    "react": "^15.5.4",
    "react-dom": "^15.5.4",
    "webpack": "^2.4.1",
    "webpack-dev-server": "^2.4.5"
  }
}

webpack.config.js

var webpack = require("webpack");
var path = require("path");
module.exports = {
        context: __dirname + "/src",
        entry: "./js/index.js",
        devServer: {
               port: 3333
        },
        module: {
            loaders: [{
                test : /\.js?$/,
                exclude : /(node_modules)/,
                loader : "babel-loader",
                query : {
                    presets : ["react", "es2015"]
                }
            }]
        },
        output : {
            path : __dirname + "/src/",
            filename : "bundle.js"
        }
};

webpack-dev-server --inline --hot

但是没有办法在localhost:3333下直接刷新 如果输入webpack-dev-server 在iframe模式下可以刷新