jQuery-ui自动完成，选择第一项

Question

I use jQuery-ui autocomplete in my rails application. When I type some input I want it to automatically select the first item in the autocomplete box. How should I implement this?

jQuery(function() {
    return $('#transaction_receiver_name').autocomplete({
        source: $('#transaction_receiver_name').data('autocomplete-source')
    });
});

My css

.ui-helper-hidden-accessible {
  display: none;
}

ul.ui-autocomplete {
  position: absolute;
  list-style: none;
  margin: 0;
  padding: 0;
  border: solid 1px #999;
  cursor: default;
  li {
    background-color: #FFF;
    color: black;
    border-top: solid 1px #DDD;
    margin: 0;
    padding: 0;
    a {
      color: #000;
      display: block;
      padding: 3px;
    }
    a.ui-state-hover, a.ui-state-active {
      background-color: #FFFCB2;
    }
  }
}

Input field

Answer 1

You just need to add autoFocus: true and it will automatically select the first element that shows in the list.

jQuery(function() {
    return $('#transaction_receiver_name').autocomplete({
        source: $('#transaction_receiver_name').data('autocomplete-source'),
        autoFocus: true
        }

    });
});

Here is an example:

 $(function() { var availableTags = [ "ActionScript", "AppleScript", "Asp", "BASIC", "C", "C++", "Clojure", "COBOL", "ColdFusion", "Erlang", "Fortran", "Groovy", "Haskell", "Java", "JavaScript", "Lisp", "Perl", "PHP", "Python", "Ruby", "Scala", "Scheme" ]; $("#tags").autocomplete({ source: availableTags, autoFocus: true, focus: function(event, ui) { event.preventDefault(); //Here you can add anycode you want to be executed when an item of the box is selected }, select: function(event, ui) { event.preventDefault(); //Code here will be executed when an item is clicked on } }); }); 

 /* this will change the style of the selected element of the box*/ .ui-autocomplete .ui-menu-item .ui-state-active { color: blue; background: red; } 

 <link href="https://code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css" rel="stylesheet" /> <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script> <input id="tags"> 

Answer 2

When the menu opens, you could collect the first list item and use that as the value. For example:

jQuery(function() {
  return $('#transaction_receiver_name').autocomplete({
    source: $('#transaction_receiver_name').data('autocomplete-source'),
    open: function(e, ui){
      var first = $(".ui-menu-item:eq(0) div").html();
      $(this).val(first);
      return false;
    }
  });
});

This is untested.

Another method is to trigger click on the first element.

jQuery(function() {
  return $('#transaction_receiver_name').autocomplete({
    source: $('#transaction_receiver_name').data('autocomplete-source'),
    open: function(e, ui){
      $(".ui-menu-item:eq(0)").trigger("click");
      return false;
    }
  });
});