This is the code I use to hide the autofill button and click it automatically when the user exits the text box where the autofill button is.

CSS

button.autofill { display: none; } /*hides the autofill button*/

Javascript

$(document).ready(function () {
  //click hidden autofill button on exit of text box 63
  $( '#Field63' ).blur(function() {
    $( ".autofill" ).trigger("click");
  });
});