Add values of checkboxes to input text field on checked

How to Add values of checkboxes to the input text field?

We stored the checkboxes value in a variable $checks, after that attach the handler to this collection. Inside the event handler, I take the collection once again and filter (return) only the checkboxes that are checked.

Jquery

$(document).ready(function(){
    $checksbx = $(":checkbox");
    $checksbx.on('change', function() {
        var string = $checksbx.filter(":checked").map(function(i,v){
            return this.value;
        }).get().join(" ");
        $('#results').val(string);
    });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text" id="results"/><br>

<input type="checkbox" value="1">1<br>
<input type="checkbox" value="2">2<br>
<input type="checkbox" value="3">3