Auto open jQuery UI autocomoplete on focus

Question

I want the autocomplete to open the drodown automatically on input focus.

Here is my example:

$(".tag-input").autocomplete({
            source: tagInputOptions,
            sortResults: true,
            select: function (event, ui) {
                var selectedValue = ui.item.value;
                if (selectedValue !== "") {
                    $(this).next(".tag-input-button").click();
                }
                return false;
            }
        }).keydown(function(event) {
            if (event.originalEvent.keyCode === 13) {
                // Enter key pressed
                event.preventDefault();
                var selectedValue = $(this).val();
                if(selectedValue !== "") {
                    $(this).next(".tag-input-button").click();
                }
            }
        }).on("focus", function () {
            $(this).autocomplete("search", " ");
        });

I have tried triggering search for it to open and it doesn´t open: $(this).autocomplete("search", " ");

I was expecting it to open with a non-filtered list.

I actually will not open and there are no errors.

Answer 1

Add minLength and focus function like this.

var tagInputOptions = [
      "ActionScript",
      "AppleScript",
      "Asp",
      "BASIC",
      "C",
      "C++",
      "Clojure",
      "COBOL",
      "ColdFusion",
      "Erlang",
      "Fortran",
      "Groovy",
      "Haskell",
      "Java",
      "JavaScript",
      "Lisp",
      "Perl",
      "PHP",
      "Python",
      "Ruby",
      "Scala",
      "Scheme"
    ];
$(".tag-input").autocomplete({
            source: tagInputOptions,
            sortResults: true,
            minLength : 0,              //add this line            
        }).keydown(function(event) {
            if (event.originalEvent.keyCode === 13) {
                // Enter key pressed
                event.preventDefault();
                var selectedValue = $(this).val();
                if(selectedValue !== "") {
                    $(this).next(".tag-input-button").click();
                }
            }
        }).focus(function() {         //add this line 
            $(this).autocomplete("search", $(this).val());
        });

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://code.jquery.com/ui/1.13.2/jquery-ui.js"></script>
<link rel="stylesheet" href="https://code.jquery.com/ui/1.13.2/themes/base/jquery-ui.css">

<div class="ui-widget">
  <label for="tags">Tags: </label>
  <input id="tags" class="tag-input">
</div>