how to get the return values from a ajax code to use inside another javascript method [duplicate]

This question already has an answer here:

• How to return the response from an asynchronous call? 7 answers

I am really new to javascript. I have this code which takes the value from the autocomplete text box and get the names related to the text from the DB. That is done in the function myFunction, this work as I expected. I have passed the data to a variable called data_set inside the ajax.

I want to get the data_set to use in another method as show in the code as getText. But data_set is empty inside the getText

<input id="autocomplete" onkeyup="myFunction()" onkeypress="showIt()">
<script>
    var data_set="";
    function myFunction() {
        var keywordx = document.getElementById("autocomplete").value;
         var data_set="";
        $.ajax({
                     type: "GET",
                     url: '/welcome/getResults/'+ keywordx,
                     data: {keyword:keywordx}, // appears as $_GET['id'] @ your backend side
                     success: function(data) {
                           // data is ur summary
                          //$('#refresh_this').html(data);
                          data_set =  data;
                          console.log(data_set);
                     }

                   });

    }   
    function getText() {
        console.log(data_set);
        }