<select name="airfromcity" class="form-control ui-autocomplete-input" id="airfromcity" autocomplete="off" style="display: none;">
    <option value="">Select one...</option>
    <option value="ABE">Allentown  PA</option>
    <option value="ABI">Abilene  TX</option>
    <option value="ABQ">Albuquerque  NM</option>
    <option value="ABR">Aberdeen  SD</option>
    <option value="ACV">Eureka  CA</option>
    <option value="ACY">Atlantic City  NJ</option>
    <option value="AEX">Alexandria  VA</option>
    <option value="AGR">Agra  India</option>
    <option value="AGS">Augusta  GA</option>
    <option value="AHN">Athens  GA</option>
    <option value="AIY">Atlantic City  NJ -Bader</option>
</select>

(function( $ ) {
    $.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: $.proxy( this, "_source" )
          })
          .tooltip({
            tooltipClass: "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"
        });
      },

      _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.data( "ui-autocomplete" ).term = "";
      },

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

  $(function() {
    $( "#airfromcity" ).combobox();
    $( "#toggle" ).click(function() {
      $( "#airfromcity" ).toggle();
    });
  });