javascript - How to dynamically add script tag in HEAD with AngularJS -

i trying dynamically add script tag in angular application. wrote function:

var injectsocketiolib = function (serveraddress) {     var wf = document.createelement('script');     wf.src = serveraddress + '/socket.io/socket.io.js';     wf.type = 'text/javascript';     wf.async = 'false';     document.head.appendchild(wf); }; 

the script injected head tag, in console following error:

referenceerror: io not defined 

how can correctly inject script in head ?

edit: if manually add script head dont error , application works correctly

resolved code script injection:

        loadscript = function (src) {             var deferred = $q.defer();             var script = $document[0].createelement('script');             script.onload = script.onreadystatechange = function (e) {                 $timeout(function () {                     deferred.resolve(e);                 });             };             script.onerror = function (e) {                 $timeout(function () {                     deferred.reject(e);                 });             };             script.src = src;             $document[0].body.appendchild(script);             return deferred.promise;         }; 

to inject script need call this:

loadscript('https://mysite.com/someplugin.js').then(function() {     // script loaded succesfully.     // can start using functions someplugin.js }).catch(function() {     // there error loading script. meh });