如何在 jQuery 组合框中强制选择文本

Question

我已经使用jQuery UI autocomplete 实现了 jQuery Combobox。
但我的目的是实现文本强制选择，我的意思是当我们输入文本时应该在匹配全文后强制选择如下所示：

下面是我使用 jQuery Combobox 实现的代码。我需要这个是因为我想在用户输入时在我的项目中使用它，如果用户输入水银并且它显示没有找到价值，它不会给出结果。

(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"
      });
    },

    _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")
        .mousedown(function() {
          wasOpen = input.autocomplete("widget").is(":visible");
        })
        .click(function() {
          input.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();
    }
  });
})(jQuery);

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

.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;

<title>jQuery UI Autocomplete - Combobox</title>
<link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css">
<script src="//code.jquery.com/jquery-1.10.2.js"></script>
<script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>
<link rel="stylesheet" href="/resources/demos/style.css">

<div class="ui-widget">
  <label>Choose Planets</label>
  <select id="combobox">
    <option value="">Select one...</option>
    <option value="Mercury">Mercury</option>
    <option value="Venus">Venus</option>
    <option value="Earth">Earth</option>
    <option value="Mars">Mars</option>
    <option value="Jupiter">Jupiter</option>
  </select>
</div>
<button id="toggle">Search</button>

Answer 1

要达到您的预期结果，请检查确切的单词，而不是通过以下代码匹配

if ( this.value == request.term )
            return {
              label: text,
              value: text,
              option: this
            };

带有有效解决方案的 Codepen URL
http://codepen.io/nagasai/pen/Lkjyyz