Solve the problem of cross-origin ajax

There are many solutions for ajax cross-origin calls. Here I will only talk about two solutions:

 

Suppose s.cnblogs.com is a comment system that only supports javascript calls. News.cnblogs.com is a news system that delegates the comment function to s.cnblogs.com. At this time, news.cnblogs.com may comment on the Code:

Function sendData (data, callback)

{

Var xmlHttp = createXmlHttpRequest ();

XmlHttp. open ('post', 'HTTP: // s.cnblogs.com/postHandler.ashx ');

XmlHttp. onreadystatechange = callback;

XmlHttp. send (data); // data contains the data to be sent.

}

This generation of code has a security reminder in IE6, but in IE7, there is a direct error. Because of cross-origin.

Solution 1: document. domain.

1. Save the senddatacode to a services.htm file. And set document. domain = 'cnblogs. com' in services.htm'

2.place services.htm under the root directory of the s.cnblogs.com website.

3. Add <iframe id = 'ajaxframe 'src = 'HTTP: // s.cnblogs.com/services.htm' width = '0' height = '0'> </iframe>

4. Add

Function sendData (data, callback)

{

AjaxFrame. window. sendData (data, callback );

}

And document. domain = 'cnblogs. com ';

Disadvantages of the solution:

Only cross-subdomain issues can be solved.

 

Solution 2: Dynamic script method.

1. Add the <script id = 'ajaxproxy 'src = ''> </script>

Function sendData (data, callback)

{

Var proxy = document. getElementById ('ajaxproxy ');

Proxy. src = 'HTTP: // s.cnblogs.com/postHandler.ashx? Data = "+ data;

Proxy. onreadystatechange = callback;

}

I personally prefer solution 2, but one problem with the solution is that callback can do too little and cannot receive the received data from postHandler. ashx.

However, I think there is a work und, that is, to directly output js in postHandler. ashx, such as alert ('OK');, but I have tested it several times before it becomes a function. It may be my RP problem.