javascript - $.ajax will not work within a function -

i having trouble function using jquery's ajax. function checks api see if variable called "success" true. if is, want function return true. if success false, want return false.

here code:

function loggedin() {     $.ajax({         type: "get",         url: "/api/auth",         success: function (a) {             if (a.success == "true") {                 return true;             } else {                 return false;             }         }     }); } 

this code in document (myjs.js, etc), , called html file after jquery , before function called. have script tag in html function called. here is:

<script type="text/javascript">     $(function() {         if (loggedin() == true) {             $('#send-to-user-btn').css('display', 'block');             $('#sign-in-button-btn').css('display', 'none');             $('#login-bar-my').css('display', 'none');         }     }); </script> 

i put console.log(loggedin()); in script tags, comes undefined.

any appreciated.

since ajax asynchronous in nature, cannot check value returned function. not guaranteed receive response api endpoint when call ajax function @ runtime.

instead, want check value when promise, returned asynchronous request, has been resolved. here can do:

1. in loggedin() function, return $.ajax() object instead. jqxhr object can add methods .done() (fired when successful), .fail() (fired when error has been encountered), or.always()` (which run upon completion).
2. since want listen success, loggedin.done(). callback in within can implement additional logic check if logged in attempt successful (i.e. checking of success key true).

using jqxhr.success callback in $.ajax discouraged now: officially deprecated in 1.8 , removed in 3.0 (and 1 of reasons why many plugins/sites break when upgrade jquery 3).

here example:

$(function() {     // return promise     var loggedin = function () {         return $.ajax({             type: "get",             url: "/api/auth"         });     };      loggedin.done(function(response) {         if (response.success) {              // if loggedin returns success             $('#send-to-user-btn').css('display', 'block');             $('#sign-in-button-btn').css('display', 'none');             $('#login-bar-my').css('display', 'none');         } else {             // otherwise...         }     }); }); 

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