No 'Access-Control-Allow-Origin' header is present on the request resource怎么解决

这个错误通常是由于跨域请求引起的。可以通过以下几种方法来解决这个问题：

1. 在服务端添加响应头 Access-Control-Allow-Origin，允许特定的域名或所有域名的访问，例如：

Access-Control-Allow-Origin: *

2. 如果使用的是 jQuery 进行 AJAX 请求，可以通过设置 `dataType: 'jsonp'` 来实现跨域请求。

3. 如果使用的是 fetch API 进行请求，可以在请求头中添加 `mode: 'cors'` 来实现跨域请求。

注意：在开发过程中，不要将 Access-Control-Allow-Origin 设置为 *，因为这会允许所有的域名访问你的服务器，可能存在安全风险。

相关问题

php No 'Access-Control-Allow-Origin' header is present on the requested resource 加了header('Access-Control-Allow-Origin: *'); 跨域还报错

在PHP中，使用header('Access-Control-Allow-Origin: *')可以解决跨域问题，但是有时候即使加了这个header也会报错。这是因为在跨域请求中，浏览器会先发送一个OPTIONS请求，来确定是否可以跨域访问。如果服务器没有正确处理这个OPTIONS请求，也会导致跨域请求失败。因此，你需要在服务器端添加对OPTIONS请求的处理，例如添加以下代码：

if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {
    header('Access-Control-Allow-Origin: *');
    header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS');
    header('Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept');
    exit;
}

这段代码会在收到OPTIONS请求时，返回允许跨域访问的header信息，从而解决跨域问题。

No 'Access-Control-Allow-Origin' header is present on the requested resource.

This error occurs when the requested resource does not include the "Access-Control-Allow-Origin" header. This header is required to allow cross-origin resource sharing (CORS) and is used to restrict which origins can access the resource.

To resolve this issue, you can add the "Access-Control-Allow-Origin" header to the server response. The value of this header should be the origin (domain) from which the request originates or "*" to allow access from any origin.

Here is an example of how to include the header in a server response using JavaScript:

response.setHeader("Access-Control-Allow-Origin", "*");

Please note that allowing access from any origin using "*" can pose security risks, so it's recommended to restrict access to specific origins whenever possible.

If you are not the owner of the server or do not have access to modify the server-side code, you can try reaching out to the server administrator or the website owner to address this issue.