first commit

2024-09-27 02:06:13 +08:00
commit 852d94fbb9
36760 changed files with 3274413 additions and 0 deletions
--- a/历届学生/陈一航/2020-04-08/ajax跨域.html
+++ b/历届学生/陈一航/2020-04-08/ajax跨域.html
@@ -0,0 +1,65 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>ajax跨域</title>
+</head>
+<body>
+    
+
+
+
+
+</body>
+
+<script>
+
+    // ajax 在调用接口的过程中会有一个访问的权限认证，这个过程叫 同源策略
+    // 同源策略 回去检查前端和后端的访问地址是否完全一致
+    // 1: 端口
+    // 2: 协议
+    // 3: 域名
+
+    // 报错
+
+    // Access to XMLHttpRequest at 'http://127.0.0.1/index.php?username=lb122&pwd=1234567890' from origin 'http://127.0.0.1:5500' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
+
+    // 解决跨域
+
+    // 1: cors
+    //    Access-Control-Allow-Origin: *
+
+    // 2: jsonp
+    //    jsonp不是ajax请求，他是js文件资源请求 + callback
+
+    // 3: 服务端代理
+    // 
+
+    // 前端：http://127.0.0.1:5500/2020-04-08/dddF.html
+    // 后端：http://127.0.0.1:80/index.php
+
+    var http = new XMLHttpRequest();
+    http.open("GET", 'http://127.0.0.1/ziji.php')
+    http.send()
+    http.onreadystatechange = function () {
+        if (http.readyState == 4 ) {  // 浏览器自带的
+            if (http.status == 200) { // 浏览器自带的
+                console.log(JSON.parse(http.responseText))
+            } else {
+              alert("网络不好")
+            }
+           
+        } 
+    }
+
+ 
+    // function getData(res) {
+    //     console.log(res)
+    // }
+
+   
+
+</script>
+<!-- <script src="http://127.0.0.1/index.php?username=lb122&pwd=1234567890&call=getData"></script> -->
+</html>