Get JSON from subdomains with jQuery -

i have user1.mydomain.com , user2.mydomain.com domains. use api.mydomain.com deal web app on ajax/json. so, want make post request user1.mydomain.com api.mydomain.com/projects using jquery this: {'action':'getactiveprojects'} list of active projects user1 in json result. found $.getjson method seems there no option sending data server, method. other problem face same origin policy. so, how can post json server on subdomain , json response result?

using $.ajax , json-p specifying datatype: "jsonp". details in linked docs. server have respond json-p rather json, that's pretty easy if control server.

alternately, if need support recent browsers (and not ie), can set server support cors. that's supported in recent browsers, , although ie8 supports it, doesn't support transparently through usual xmlhttprequest object, instead requires different transport object (xdomainrequest), jquery doesn't handle automatically (yet).

here's json-p example using jquery:

$.ajax({   // source url   url: "http://jsbin.com/ubucu4",    // tell jquery you're doing json-p   datatype: "jsonp",    // include data request if like;   // example doesn't *use* data   data: {some: "data"},    // can control name of callback,   // don't want , jquery handle   // you. have here because i'm doing   // example on jsbin.   jsonpcallback: "examplecallback",    // success callback   success: function(data) {     display("received data, typeof data = " + typeof data);     display("data.foo = " + data.foo);     display("data.bar = " + data.bar);   },    // error callback         error: function(jxhr, status, err) {     display("error, status = " + status + ", err = " + err);   } }); 

live copy

on server, you'll see jquery has added callback parameter url, e.g. in above http://jsbin.com/ubucu4?callback=examplecallback if jquery control name bit more exotic. server-side code should construct response javascript function call, calling function. response in above example is:

examplecallback({     "foo": "this foo",     "bar": "this bar" }); 

this happens because instead of using xmlhttprequest, subject same origin policy, json-p uses dynamically-added script tag (which fine). in example, tag like

<script type='text/javascript' src='http://jsbin.com/ubucu4?callback=examplecallback'></script> 

the browser retrieve script, json-p response, , execute it. means callback gets called, , data supplied script.

your json-p response isn't, technically, json; it's javascript, , reasons it's essential use json-p servers trust (such own subdomain servers), since you're injecting code directly page. otherwise, if you're using server can't trust, code gets injected may read information off page , send third party. let caution watchword.