JS cross-Domain detailed

Thank Rain Man from the gardenThis guy, the information is very detailed:

For details, see: HTTP://WWW.CNBLOGS.COM/RAINMAN/ARCHIVE/2011/02/20/1959325.HTML#M0

I picked out part of my own collection:

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What is a cross-domain

JavaScript is not allowed to invoke objects of other pages across domains for security reasons. But the security restrictions also bring a lot of trouble to inject IFRAME or AJAX applications. Here are some simple things to sort out about cross-domain issues:

First what is cross-domain, simple to understand is because of the JavaScript homologous policy limitations, a.com domain name JS can not operate B.Com or c.a.com under the domain name of the object. A more detailed explanation can be seen in the following table:

URL	Description	whether to allow communication
http://www.a.com/a.js http://www.a.com/ B.js	under the same domain name	allow
http://www.a.com/lab/a.js Http://www.a.com/script/b.js	different folders under the same domain name	Allow
http://www.a.com:8000/a.js http://www.a.com/b.js	same domain name, different ports	do not allow
http://www.a.com/a.js https://www.a.com/b.js	same domain name, different protocol	does not allow
http://www.a. Com/a.js http://70.32.92.74/b.js	domain name and domain name corresponding IP	do not allow
http://www.a.com/a.js H Ttp://script.a.com/b.js	primary domain, subdomain different	not allowed
http://www.a.com/a.js http://a.com/ B.js	Same domain name, different level two domain name (ibid.)	not allowed (cookies are not allowed in this case)
http://www.cnblogs.com/a.js H Ttp://www.a.com/b.js	different domain names	not allowed

Pay special attention to two points:

First, if it is a cross-domain problem caused by protocol and port "front desk" is powerless,

Second: On a cross-domain issue, the domain is only identified by the "header of the URL" and does not attempt to determine whether the same IP address corresponds to two domains or two domains on the same IP.
The "header of the url" refers to Window.location.protocol +window.location.host, which can also be understood as "Domains, protocols and ports must match".

The next simple summary of the "front office" generally handle cross-domain approach, background proxy This scenario involves the background configuration, here does not elaborate

JS cross-Domain detailed