title: webpack dev server listening a file with extension PHP ( "index.php")
body: <p>everybody.</p>
  
  <p>I am using the default configuration, without any additional packages.</p>
  
  <p>After a run of command, "npm run dev" have opened the file PHP like a page in the browser but file have downloaded.</p>
  
  <p>How I can setting config, that dev server could be listening to a file with an extension of PHP?</p>
  
  <p>Config:</p>
  
  <pre><code>    let path = require('path');
  
  let conf = {
      entry: './panel/js/index.js',
      output: {
          path: path.join( __dirname, 'panel/js' ),
          publicPath: '/panel/',
          filename: 'bundle.js'
      },
      devServer: {
        index: '',
        open: true,
        overlay: {
          warnings: true,
          errors: true
        },
        host: 'test.io',
        proxy: {
          '**': {
            target: 'https://test.io',
            changeOrigin: true,
          }
        }
      }
  };
  
  module.exports = conf;
  </code></pre>
  
  <p>package.json:</p>
  
  <pre><code>{
    "name": "js",
    "version": "1.0.0",
    "description": "",
    "main": "login-js.js",
    "scripts": {
      "dev": "webpack-dev-server --inline --hot --mode development --open",
      "build": "webpack --mode production",
      "start": "cross-env NODE_ENV=development webpack-dev-server --inline"
    },
    "author": "",
    "license": "ISC",
    "devDependencies": {
      "cross-env": "^5.2.0",
      "path": "^0.12.7",
      "webpack": "^4.17.1",
      "webpack-cli": "^3.1.0",
      "webpack-dev-server": "^3.1.5"
    },
    "dependencies": {
      "jquery": "^3.3.1"
    }
  }
  </code></pre>
  
  <p>Thank's for help.</p>