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

Copy code The code is as follows:

<script>window.name='{"id":"3", "name":"leisure"}';&lt ;/script> <br>2. Define an iframe and add onload event<iframe id="iframe1" onload="iLoad"><iframe> <br><script type="text/javascript"> <br>var load = false; <br>function iLoad() { <br>if(load == false) { <br>// Same domain processing, the iframe will be reloaded again after the request <br>document.getElementById( 'iframe1').contentWindow.location = '/'; <br>load = true; <br>} else { <br>// Get the content of window.name. Note that it must be accessed after the same domain processing! <br>var data = document.getElementById('iframe1').contentWindow.name; <br>alert(data); // {"id":"3", "name":"leisure"} <br>load = false; <br>} <br>} <br></script>

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

Copy code The code is as follows:

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

Copy code The code is as follows:

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

Copy code The code is as follows:

$.getJSON(url " ?callback=?", data, function(data) {
}

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

Copy code The code is as follows: