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xhr与fetch异步实例演示 模块成员导出与导入 别名使用场景与命名空间实例演示
早晨
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传统 XHR

  1. 创建对象: new XMLHttpRequest();
  2. 响应类型: xhr.responseType = "json";
  3. 配置参数: xhr.open("GET", url, true);
  4. 请求回调: xhr.onload = () => console.log(xhr.response);
  5. 失败回调: xhr.onerror = () => console.log("Error");
  6. 发起请求: xhr.send(null);
    xhr 至少监听2个事件: load,error, 调用2个函数: open,send
    post请求,需要设置一下请求头与请求的数据,其它与get请求完全相同

fetch

fetch api : 浏览器原生实现的异步技术
axios: 基于 xhr / fetch
fetch: 基于Promise, 返回 Promise对象

演示实例代码

  1. <!DOCTYPE html>
  2. <html lang="zh-CN">
  3. <head>
  4. <meta charset="UTF-8" />
  5. <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  6. <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  7. <title>xhr与fetch异步编程实例演示</title>
  8. </head>
  9. <body style="display: grid; gap: 1.5em">
  10. <button onclick="getxhr(this)">XHR同步</button>
  11. <button onclick="getfetch(this)">FETCH同步</button>
  12. <script>
  13. function getxhr(btn) {
  14. // 1. 创建对象
  15. const getxhr = new XMLHttpRequest();
  16. // 2. 响应类型
  17. getxhr.responseType = "json";
  18. // 3. 配置参数
  19. let url = "https://jsonplaceholder.typicode.com/users";
  20. // url = "https://jsonplaceholder.typicode.com/todos/1";
  21. getxhr.open("GET", url, true);
  22. // 4. 请求回调
  23. getxhr.onload = () => console.log(getxhr.response);
  24. // 5. 失败回调
  25. getxhr.onerror = () => console.log("Error");
  26. // 6. 发起请求
  27. getxhr.send(null);
  28. console.log("---------------------XHR同步---------------------------");
  29. }
  30. function getfetch(btn) {
  31. fetch("https://jsonplaceholder.typicode.com/todos/1")
  32. .then((response) => response.json())
  33. .then((json) => console.log(json));
  34. console.log("----------------------FETCH同步------------------------");
  35. }
  36. </script>
  37. </body>
  38. </html>

运行效果

模块成员导出与导入演示实例代码

  1. <!DOCTYPE html>
  2. <html lang="zh-CN">
  3. <head>
  4. <meta charset="UTF-8" />
  5. <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  6. <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  7. <title>模块成员导出与导入</title>
  8. </head>
  9. <body>
  10. <script type="module">
  11. import { name, abc } from "./m1.js";
  12. console.log(name);
  13. console.log(abc(name));
  14. </script>
  15. </body>
  16. </html>

js代码(m1.js)

  1. // 声明
  2. let name = "早上好";
  3. function abc(name) {
  4. return `老师, ${name}`;
  5. }
  6. // 导出
  7. export { name, abc };

运行效果

模块别名导出演示实例代码

  1. <!DOCTYPE html>
  2. <html lang="zh-CN">
  3. <head>
  4. <meta charset="UTF-8" />
  5. <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  6. <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  7. <title>模块别名导出</title>
  8. </head>
  9. <body>
  10. <script type="module">
  11. import { myuser, obq } from "./m2.js";
  12. console.log(myuser);
  13. console.log(obq(myuser));
  14. </script>
  15. </body>
  16. </html>

js代码(m2.js)

  1. // 声明
  2. let user = "别名导出";
  3. function abc(user) {
  4. return `这个是, ${user}`;
  5. }
  6. // 别名导出
  7. export { user as myuser, abc as obq };

运行效果

模块命名空间演示实例代码

  1. <!DOCTYPE html>
  2. <html lang="zh-CN">
  3. <head>
  4. <meta charset="UTF-8" />
  5. <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  6. <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  7. <title>模块命名空间</title>
  8. </head>
  9. <body>
  10. <script type="module">
  11. import * as phpname from "./m3.js";
  12. console.log("------------------模块所有成员-------------------------");
  13. console.log(phpname);
  14. console.log("------------------模块成员----------------------------");
  15. console.log(phpname.name);
  16. console.log(phpname.tel(phpname.name));
  17. console.log("------------------访问默认----------------------------");
  18. console.log(phpname.default);
  19. </script>
  20. </body>
  21. </html>

js代码(m3.js)

  1. let name = "命名空间";
  2. function tel(name) {
  3. return `这个是, ${name}`;
  4. }
  5. let email = "xxxxxx@xxx.com";
  6. let status = "1";
  7. export { name, tel, email as default };

运行效果

Correcting teacher:PHPzPHPz

Correction status:qualified

Teacher's comments:
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