The code is as follows:

$.ajax({
		type:'post',
		url:url,
		data:data,
		dataType:'json',
		xhrFields:{
withCredentials:true
/*
Corresponds to the code in the server
response.addHeader("Access-Control-Allow-Credentials","true");
		response.addHeader("Access-Control-Allow-Origin",origin);
*/
},
crossDomain:true,
success:function(res){
	//。。。
},
error:function(resData){
	//。。。。
}
	});

Open chrome, open fiddler, visit the page, click the button to run, the browser seems to be normal, Fiddler gets an http200 ~! It seems that cross domain access can be achieved by setting crossdomain = true, but it is not perfect

Open IE, test again,,, report an error!?There is no response in fiddler, even the request is not sent out. Strange?Google… Found in an article in stackoverflow:

http://stackoverflow.com/questions/3362474/jquery-ajax-fails-in-ie-on-cross-domain-calls

In other words, IE8 uses the so-called xdomainrequest instead of XMLHttpRequest, but jQuery only supports XMLHttpRequest

At present, the best solution is to use jsonp