无法获得Ajax响应

Question

I am using javascript and php to run an Ajax code. The result at the moment is undefined.

I am using localStorage to move the variable from the Ajax function because I cannot understand the use of a callback (I have followed numerous examples of using callbacks but none ever worked. I figured this solution might be the least complex.

Javascript:

$( document ).ready(function() {

   $('#submit-values').click(function(e){
        /************************************************************* SUBMIT */
        e.preventDefault();//Stop page reload on click

        $('#put-output-here').val(createParagraph());

   });

   function createParagraph(){
        createSentence();
        return localStorage.getItem('sentence');
   }

   function createSentence(){
        $.when(ajax1()).done(function(a1){
            localStorage.setItem('sentence', a1);
        })
   }

   function ajax1(){
       $.post("word-engine.php",
        {

        },
        function(data){
        });
   }
});

PHP:

<?php
    $chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';


    $randomString = '';
    for($x = 0; $x < 10; $x++){
        $rand = rand(0,62);
        $randomString = $randomString.$chars[$rand];
    }
    echo $randomString;

?>

At the moment my result is undefined

Answer 1

use this: since $.post is a asynchronous function. The control from function will immediately return after it run post but the response from post may be received later.

function ajax1(){
   $.post("word-engine.php",
    {

    },
    function(data){
        setdata(data);
    });
}

function setdata(data){
    localStorage.setItem('sentence', data);
}

note: for more info see this post:why cant I return data from $.post (jquery)