jQuery synchronous Ajax request returns 'undefined' -

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this question has answer here:

i trying jquery synchronous ajax call return boolean value, when test return value 'undefined'.

jquery code:

function foo() {     var username = "hello"     if (checkusernameexist(username)) {         //do here     } }  function checkusernameexist(username) {     return $.ajax({         type: 'post',         url: "check_username.php",         data: { username: username},         async: false,     }).responetext; }

php code:

<?php     //sets connection (among other things) include 'common.php';  //check have username post var if(isset($_post['username'])) {     //check if ajax request, exit if not     if(!isset($_server['http_x_requested_with']) , strtolower($_server['http_x_requested_with']) != 'xmlhttprequest') {         die();     }      $un = $_post['username'];      //check username in db     $results = pg_query($con,"select * users username='{$un}'");      //return total count     $username_exist = pg_num_rows($results); //total records      if ($username_exist == 1) {         echo true;     } else {         echo false;     } } ?>

thanks in advance.

i use success call , works:

function checkusernameexist(username) {      var exists;      $.ajax({         type: 'post',         url: "check_username.php",         data: { username: username},         async: false,         success: function(response){          exists =  response;         }     })   reutrn exists; }

note:

it's not recommended practice make ajax calls synchronous halt ui on browser. if ajax call takes long complete, user won't able on website until it's done.


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