JS-cross-domain

cross-domain error: xmlhttprequest cannot load ' url '. No ' Access-control-allow-origin ' header is present on the requested resource. Origin ' URL ' is therefore not allowed access.

What is cross-domain: protocol, subdomain, primary domain, port number, any one of which is not the same, counted as cross-domain.

Cause: JS is not allowed to invoke objects of other pages across domains for security reasons. (same-Origin policy limit)

Workaround:

1. Agent: by creating a proxy on the Web server side of the same domain name

Own:http://www.abc.com

Others ':http://www.bcd.com

When you access your own server (http://www.abc.com/proxy-service.php), your own server (http://www.abc.com/proxy-service.php) calls someone else's service ( http://www.bcd.com/service.php) so that the front-end calls its own server, which is equivalent to calling someone else's server.

2, JSONP: (JSONP cross-domain request support GET request)

Jsonp can be used to address cross-domain data access issues in mainstream browsers:

The server JS file to load the cross-domain JS file, cross-domain JS file return JSONP, is to avoid cross-domain problems.

Front-end Code: $.ajax ({    type: "Get",    //Use JSONP cross-domain request only support GET request    URL: "Cross domain Address",    dataType: "Jsonp",    Jsonp: " Callback ",    success:function () {        if (data.sueccess) {            //parse Jsonp        }else{        }    },    error: function (JQXHR) {        Console.log ("Error occurred:" +jqxhr.status);    

3, XHR2:

The XMLHttpRequest Level2 provided by HTML5 has implemented cross-domain access and a number of other new features

IE10 versions below are not supported

• Make some minor changes on the server side: (PHP)

Header (' access-control-allow-origin:* ');

Header (' Access-control-allow-methods:post,get ');

JS-cross-domain