:5173/#/login:1 Access to XMLHttpRequest at 'http://127.0.0.1:8000/login/register' from origin 'http://localhost:5173' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

时间: 2023-11-23 14:35:58 浏览: 207

XMLHttpRequest_test:XMLHttpRequest学习代码

XMLHttpRequest（XHR）是Web开发中的一个关键技术，它允许JavaScript在不刷新整个页面的情况下与服务器进行异步数据交换。这个技术对于实现动态网页和Ajax（Asynchronous JavaScript and XML）应用至关重要。"XMLHttpRequest_test"是一个学习项目，专门针对XMLHttpRequest进行实践操作。在JavaScript中，XMLHttpRequest对象用于创建后台与服务器端的通信。以下是一些关于XMLHttpRequest的重要知识点： 1. **创建XMLHttpRequest对象**：在JavaScript中，可以通过`new XMLHttpRequest()`来创建一个实例。虽然名字中有XML，但如今它并不限于处理XML数据，而是可以处理各种格式的数据，如JSON、文本等。 2. **初始化请求**：使用`open()`方法来初始化一个HTTP请求。`open(method, url, asynchronous)`，参数包括请求类型（GET、POST等）、URL以及是否异步执行。例如，`xhr.open('GET', 'test.php', true);` 3. **设置请求头**：使用`setRequestHeader()`方法可以设置HTTP请求头。例如，如果发送JSON数据，需要设置`Content-Type`为`application/json`。 4. **发送请求**：调用`send()`方法发送请求。GET请求无需传递参数，POST请求可以传入数据。例如，`xhr.send(null)`或`xhr.send(JSON.stringify(data))`。 5. **监听状态变化**：通过`onreadystatechange`事件监听XMLHttpRequest的状态。当`readyState`属性变化时，该事件会被触发。`readyState`有5个状态值，其中4表示数据已加载，可以访问响应。 6. **获取响应**：当请求完成，可以通过`responseText`或`responseXML`属性获取服务器返回的数据。数据类型取决于请求头中的`Accept`字段。 7. **错误处理**：可以设置`onerror`事件处理程序来捕获请求失败的情况。同时，`onreadystatechange`事件中，可以检查`status`属性判断HTTP状态码，如404（未找到）或500（内部服务器错误）。 8. **跨域请求**：默认情况下，XMLHttpRequest遵循同源策略，不允许跨域。但通过CORS（Cross-Origin Resource Sharing）机制，服务器可以允许特定的跨域请求。 9. **Promise化使用**：现代浏览器中的XMLHttpRequest已经被Fetch API部分替代，Fetch API返回Promise，使得异步操作更加简洁易读。但XMLHttpRequest仍被广泛使用，特别是在需要兼容旧版浏览器时。在"XMLHttpRequest_test-master"这个项目中，你可以期待看到如何运用这些概念来构建实际的Ajax请求，可能包括向服务器发送数据、处理响应、展示结果等。通过这个测试项目，你可以深入理解XMLHttpRequest的工作原理，并提升你的JavaScript编程技能。

这是一个跨域请求的错误。出现这个错误是因为浏览器的同源策略限制了不同域之间的访问。解决这个问题需要在服务器端设置响应头，允许特定的域名进行跨域访问。你可以在服务器端设置Access-Control-Allow-Origin响应头为"http://localhost:5173"，这样就可以解决这个错误了。另外，你可以使用JSONP或者CORS来实现跨域请求。

阅读全文

:5173/#/login:1 Access to XMLHttpRequest at 'http://127.0.0.1:8000/login/register' from origin 'http://localhost:5173' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

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jquery-1.7.2.min.zip_JavaScript/JQuery_C#_

为什么我发送post请求给后端:8080/#/home/cardlist:1 Access to XMLHttpRequest at 'http://127.0.0.1:8888/api/add' from origin 'http://localhost:8080' has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.

:9527/#/login?redirect=%2Fdashboard:1 Access to XMLHttpRequest at 'http://192.168.0.139:5000/login/' from origin 'http://localhost:9527' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Access to XMLHttpRequest at 'http://localhost:8081/api/login' from origin 'http://localhost:8080'

Access to XMLHttpRequest at 'http://localhost:8082/api/user/login' from origin 'http://localhost:9527' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource

Access to XMLHttpRequest at 'http://localhost:8000/' 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.

http://localhost/#/login

Access to XMLHttpRequest at 'http://127.0.0.1/hy_app_api/index/banner.php' from origin 'http://localhost:5173' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Access to XMLHttpRequest at 'http://192.168.1.6:3002/accounts/login/' from origin 'http://localhost:8081' has been blocked by CORS

Access to XMLHttpRequest at 'http://localhost:9999/user/login' from origin 'http://localhost:8888' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Access to XMLHttpRequest at 'http://127.0.0.1:8000/points' from origin 'http://127.0.0.1:8080' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Access to XMLHttpRequest at 'https://duck.icu/v1/api/oauth2/logout' from origin 'http://127.0.0.1:5173' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Access to XMLHttpRequest at 'http://192.168.4.39:8088/case/login' from origin 'http://localhost:9528' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. 翻译

Access to XMLHttpRequest at 'http://101.42.24.92/account/categories' from origin 'http://127.0.0.1:5173' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. 什么意思，如何解决

Access to XMLHttpRequest at 'http://127.0.0.1/test1/php/content.php' from origin 'http://localhost:63342' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

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