Autocomplete list passed in from HTML input tag not showing

Autocomplete list passed in from HTML input tag not showing

I am using the followng default autocomplete code passing in a variable that consists of a list of XML filenames, but the list is not showing up in the autocomplete box.  The jquery code is also interpreting the variable as a literal instead of the values which are the XML filenames.
Can you suggest fixes for both ot the issues?:

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>jQuery UI Autocomplete - Default functionality</title>
  <link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
  <link rel="stylesheet" href="/resources/demos/style.css">
  <script>
  $( function() {
    $( "#tags" ).autocomplete({
      source: $('#txtEmail').val();
    });
  } );
  </script>
</head>
<body>
<div class="ui-widget">
  <label for="tags">Tags: </label>
  <input id="tags">
  <input type="text" id="txtEmail" class="textbox" value={{msg.payload}}>
</div>
</body>
</html>