demos/autocomplete/combobox.html

<!doctype html>
<html lang="en">
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title>jQuery UI Autocomplete - Combobox</title>
	<link rel="stylesheet" href="../../themes/base/all.css">
	<link rel="stylesheet" href="../demos.css">
	<style>
	.custom-combobox {
		position: relative;
		display: inline-block;
	}
	.custom-combobox-toggle {
		position: absolute;
		top: 0;
		bottom: 0;
		margin-left: -1px;
		padding: 0;
	}
	.custom-combobox-input {
		margin: 0;
		padding: 5px 10px;
	}
	</style>
	<script src="../../external/requirejs/require.js"></script>
	<script src="../bootstrap.js" data-modules="tooltip button">
		$.widget( "custom.combobox", {
			_create: function() {
				this.wrapper = $( "<span>" )
					.addClass( "custom-combobox" )
					.insertAfter( this.element );

				this.element.hide();
				this._createAutocomplete();
				this._createShowAllButton();
			},

			_createAutocomplete: function() {
				var selected = this.element.children( ":selected" ),
					value = selected.val() ? selected.text() : "";

				this.input = $( "<input>" )
					.appendTo( this.wrapper )
					.val( value )
					.attr( "title", "" )
					.addClass( "custom-combobox-input ui-widget ui-widget-content ui-state-default ui-corner-left" )
					.autocomplete({
						delay: 0,
						minLength: 0,
						source: this._source.bind( this )
					})
					.tooltip({
						classes: {
							"ui-tooltip": "ui-state-highlight"
						}
					});

				this._on( this.input, {
					autocompleteselect: function( event, ui ) {
						ui.item.option.selected = true;
						this._trigger( "select", event, {
							item: ui.item.option
						});
					},

					autocompletechange: "_removeIfInvalid"
				});
			},

			_createShowAllButton: function() {
				var input = this.input,
					wasOpen = false;

				$( "<a>" )
					.attr( "tabIndex", -1 )
					.attr( "title", "Show All Items" )
					.tooltip()
					.appendTo( this.wrapper )
					.button({
						icons: {
							primary: "ui-icon-triangle-1-s"
						},
						text: false
					})
					.removeClass( "ui-corner-all" )
					.addClass( "custom-combobox-toggle ui-corner-right" )
					.on( "mousedown", function() {
						wasOpen = input.autocomplete( "widget" ).is( ":visible" );
					})
					.on( "click", function() {
						input.trigger( "focus" );

						// Close if already visible
						if ( wasOpen ) {
							return;
						}

						// Pass empty string as value to search for, displaying all results
						input.autocomplete( "search", "" );
					});
			},

			_source: function( request, response ) {
				var matcher = new RegExp( $.ui.autocomplete.escapeRegex(request.term), "i" );
				response( this.element.children( "option" ).map(function() {
					var text = $( this ).text();
					if ( this.value && ( !request.term || matcher.test(text) ) )
						return {
							label: text,
							value: text,
							option: this
						};
				}) );
			},

			_removeIfInvalid: function( event, ui ) {

				// Selected an item, nothing to do
				if ( ui.item ) {
					return;
				}

				// Search for a match (case-insensitive)
				var value = this.input.val(),
					valueLowerCase = value.toLowerCase(),
					valid = false;
				this.element.children( "option" ).each(function() {
					if ( $( this ).text().toLowerCase() === valueLowerCase ) {
						this.selected = valid = true;
						return false;
					}
				});

				// Found a match, nothing to do
				if ( valid ) {
					return;
				}

				// Remove invalid value
				this.input
					.val( "" )
					.attr( "title", value + " didn't match any item" )
					.tooltip( "open" );
				this.element.val( "" );
				this._delay(function() {
					this.input.tooltip( "close" ).attr( "title", "" );
				}, 2500 );
				this.input.autocomplete( "instance" ).term = "";
			},

			_destroy: function() {
				this.wrapper.remove();
				this.element.show();
			}
		});

		$( "#combobox" ).combobox();
		$( "#toggle" ).on( "click", function() {
			$( "#combobox" ).toggle();
		});
	</script>
</head>
<body>

<div class="ui-widget">
	<label>Your preferred programming language: </label>
	<select id="combobox">
		<option value="">Select one...</option>
		<option value="ActionScript">ActionScript</option>
		<option value="AppleScript">AppleScript</option>
		<option value="Asp">Asp</option>
		<option value="BASIC">BASIC</option>
		<option value="C">C</option>
		<option value="C++">C++</option>
		<option value="Clojure">Clojure</option>
		<option value="COBOL">COBOL</option>
		<option value="ColdFusion">ColdFusion</option>
		<option value="Erlang">Erlang</option>
		<option value="Fortran">Fortran</option>
		<option value="Groovy">Groovy</option>
		<option value="Haskell">Haskell</option>
		<option value="Java">Java</option>
		<option value="JavaScript">JavaScript</option>
		<option value="Lisp">Lisp</option>
		<option value="Perl">Perl</option>
		<option value="PHP">PHP</option>
		<option value="Python">Python</option>
		<option value="Ruby">Ruby</option>
		<option value="Scala">Scala</option>
		<option value="Scheme">Scheme</option>
	</select>
</div>
<button id="toggle">Show underlying select</button>

<div class="demo-description">
<p>A custom widget built by composition of Autocomplete and Button. You can either type something into the field to get filtered suggestions based on your input, or use the button to get the full list of selections.</p>
<p>The input is read from an existing select-element for progressive enhancement, passed to Autocomplete with a customized source-option.</p>
<p>This is not a supported or even complete widget. Its purely for demoing what autocomplete can do with a bit of customization. <a href="https://www.learningjquery.com/2010/06/a-jquery-ui-combobox-under-the-hood">For a detailed explanation of how the widget works, check out this Learning jQuery article.</a></p>
</div>
</body>
</html>