4 solutions to Javascript cross-domain requests_javascript skills

Under what circumstances does cross-domain occur?
Assume the domain name is: http://www.example.com.cn/
If the requested domain name is different from this domain name, this situation is cross-domain. Since there are loopholes in cross-domain, it is generally normal. The cross-domain request method cannot be requested.
Solution:
1. window.name
1. The server returns

3. Define a form, set the form's target to the id of the iframe, and then submit the form

2. JSONP
The server returns callback({"id": "3", "name": "leisure"});

3. jQuery.getJSON
The server returns json format data test({"id": "3", "name": "leisure"}); test function The name is defined in the callback parameter

Note that the callback=? parameter must be brought, jquery will automatically generate a function name to replace the question mark! jQuery.getJSON It is actually implemented using JSONP.
4. Flash cross-domain
Add crossdomain.xml to the server
http://www.example.com.cn/crossdomain.xml