Reactjs 在我的react应用程序中，它给出了一个错误，即react和reactDOM未定义_Reactjs

Reactjs 在我的react应用程序中，它给出了一个错误，即react和reactDOM未定义

reactjs

Reactjs 在我的react应用程序中，它给出了一个错误，即react和reactDOM未定义,reactjs,Reactjs,我开始创建一个react应用程序，它给出了一个错误，react和ReactDOM没有定义。我正在这里添加我的代码` <head> <meta charset="UTF-8"> <title>Indecision App</title> </head> <body> <div id="app"></div>

我开始创建一个react应用程序，它给出了一个错误，react和ReactDOM没有定义。我正在这里添加我的代码`

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`

您尚未定义ReactDOM

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`

用这个替换你的代码

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`

import React from "react";
import ReactDOM from "react-dom";
var template = React.createElement("h1", {
  id: "id"
  }, "This is jsx from app.js")
 var appRoot = document.getElementById('root');
 ReactDOM.render(template,appRoot);

下面的代码工作正常

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`

index.html

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Document</title>
  </head>
  <body>
    <div id="app"></div>
    <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
    <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"></script>
    <script src="./scripts/app.js"></script>
  </body>
</html>

文件夹结构

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`

用你的app.js代码替换你的app.js代码是受欢迎的，如果这有用，请接受正确的答案

        <head>
        <meta charset="UTF-8">
        <title>Indecision App</title>
       </head>

      <body>
      <div id="app"></div>
          <script src="https://unpkg.com/react@16.12.0/umd/react.development.js"></script>
          <script src="https://unpkg.com/react-dom@16.12.0/umd/react-dom.development.js"> 
          </script>
           <script src="/scripts/app.js"></script>

         </body>

          </html>`