JS cross-Domain access hint error: XMLHttpRequest cannot load/http/... No ' Access-control-allow-origin ' header is present on the requested resource. Origin ' null ' is therefore not allowed access.
Workaround:
1. If the requested URL is an ASPX page, you will need to add code to the ASPX page: Response.AddHeader ("Access-control-allow-origin", "*");
2, if the requested URL is a PHP page, you need to add code in the PHP page: Header ("Access-control-allow-origin: *"); "I use PHP, this method to solve the problem"
3. If the requested URL is a static HTML page, you will need to add a META tag code to the page: <meta http-equiv= "Access-control-allow-origin" content= "*"/>
If the server side can determine which domain name to be accessed, it is best to replace the "*" in the above code for the specific domain name, so that the security can be enhanced accordingly.
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The latest in the global standard is how to implement HTTP cross-domain requests, cross-origin Resource sharing
Simply put, the cross-domain target server returns a series of headers that control whether the cross-domain is agreed by the headers. These headers are: 4 Syntax
4.1 Access-Control-Allow-Origin
HTTP Response Header
4.2 Access-Control-Max-Age
HTTP Response Header
4.3 Access-Control-Allow-Credentials
HTTP Response Header
4.4 Access-Control-Allow-Methods
HTTP Response Header
4.5 Access-Control-Allow-Headers
HTTP Response Header
4.6 Origin
HTTP Request Header
4.7 Access-Control-Request-Method
HTTP Request Header
4.8 Access-Control-Request-Headers
HTTP Request Header
There are some in the Request package and in the Response package.
One of the most sensitive is the access-control-allow-origin Header, which is used to check whether the cross-domain request can be passed. (Access Control Check)
The process for cross-domain implementations is roughly as follows:
Initiate a cross-domain request from http://www.a.com/test.html ,
The requested address is: http://www.b.com/test.php
If Server B Returns a header like the following
Access-control-allow-origin:http://www.a.com
Then, the cross-domain request from http://www.a.com/test.html will be passed.
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Original link: http://zjblogs.com/js/Access-Control-Allow-Origin.html
JS cross-domain access, No ' Access-control-allow-origin ' header is present on the requested resource