添加标题到select2下拉

Question

我的JSP页面及其选项中有一个select2下拉列表。我想在选项更改时为该select2下拉列表添加标题。我尝试添加标题。但当我将鼠标悬停在select2框上时，标题不会出现。但是title属性会附加到select2下拉列表中。请帮我解决这个问题。

<select id="daySelect" title="select your day">
 <option val="0">Sunday</option>
 <option val="1">Monday</option>
 <option val="2">Tuesday</option>
 <option val="3">Wednesday</option>
 <option val="4">Thursday</option>
 <option val="5">Friday</option>
 <option val="6">Saturday</option>
</select>

Answer 1

  

标题未被复制到用于显示选项的范围   select2版本3.5。*

但是，您可以按如下方式更改select2.js： -

populateResults: function(container, results, query) {
                var populate, id=this.opts.id, liveRegion=this.liveRegion;

                populate=function(results, container, depth) {

                    var i, l, result, selectable, disabled, compound, node, label, innerContainer, formatted;

                    results = opts.sortResults(results, container, query);

                    // collect the created nodes for bulk append
                    var nodes = [];
                    for (i = 0, l = results.length; i < l; i = i + 1) {

                        result=results[i];

                        disabled = (result.disabled === true);
                        selectable = (!disabled) && (id(result) !== undefined);

                        compound=result.children && result.children.length > 0;

                        node=$("<li></li>");
                        node.addClass("select2-results-dept-"+depth);
                        node.addClass("select2-result");
                        node.addClass(selectable ? "select2-result-selectable" : "select2-result-unselectable");
                        if (disabled) { node.addClass("select2-disabled"); }
                        if (compound) { node.addClass("select2-result-with-children"); }
                        node.addClass(self.opts.formatResultCssClass(result));
                        node.attr("role", "presentation");

                        label=$(document.createElement("div"));
                        label.addClass("select2-result-label");
                        label.attr("id", "select2-result-label-" + nextUid());
                        label.attr("role", "option");
                        if(result.element.length > 0 && result.element[0].title != undefined)
                            label.attr("title", result.element[0].title || '');

                        formatted=opts.formatResult(result, label, query, self.opts.escapeMarkup);
                        if (formatted!==undefined) {
                            label.html(formatted);
                            node.append(label);
                        }


                        if (compound) {
                            innerContainer=$("<ul></ul>");
                            innerContainer.addClass("select2-result-sub");
                            populate(result.children, innerContainer, depth+1);
                            node.append(innerContainer);
                        }

                        node.data("select2-data", result);
                        nodes.push(node[0]);
                    }

                    // bulk append the created nodes
                    container.append(nodes);
                    liveRegion.text(opts.formatMatches(results.length));
                };

                populate(results, container, 0);
            }

这一行更改正是我们所需要的： -

 if(result.element != undefined && result.element.length > 0 && result.element[0].title != undefined)
                            label.attr("title", result.element[0].title || '');

Answer 2

简单，在更改时添加select的当前值作为其标题属性

运行代码段，更改选项并将鼠标悬停在您可以看到更改的选择

上

＆＃13;

＆＃13;

$('#daySelect').change(function(){
	 $(this).next().attr('title',$(this).val());
	});
	$('#daySelect').select2().change();

＆＃13;

<link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.min.css" rel="stylesheet"/>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.full.min.js"></script>
 <select id="daySelect">
	 <option val="0">Sunday</option>
	 <option val="1">Monday</option>
	 <option val="2">Tuesday</option>
	 <option val="3">Wednesday</option>
	 <option val="4">Thursday</option>
	 <option val="5">Friday</option>
	 <option val="6">Saturday</option>
</select>

＆＃13;

＆＃13;

＆＃13;

Answer 3

检查一下它可能会对你有所帮助！

$('#selectb').select2({
    placeholder: 'Please select ...',
    allowClear: true
}).val(null).trigger('change');
 $( document ).tooltip();

.select2-container {
  box-sizing: border-box;
  display: inline-block;
  margin: 0;
  position: relative;
  vertical-align: middle; }
  .select2-container .select2-selection--single {
    box-sizing: border-box;
    cursor: pointer;
    display: block;
    height: 28px;
    user-select: none;
    -webkit-user-select: none; }
    .select2-container .select2-selection--single .select2-selection__rendered {
      display: block;
      padding-left: 8px;
      padding-right: 20px;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap; }
  .select2-container[dir="rtl"] .select2-selection--single .select2-selection__rendered {
    padding-right: 8px;
    padding-left: 20px; }
  .select2-container .select2-selection--multiple {
    box-sizing: border-box;
    cursor: pointer;
    display: block;
    min-height: 32px;
    user-select: none;
    -webkit-user-select: none; }
    .select2-container .select2-selection--multiple .select2-selection__rendered {
      display: inline-block;
      overflow: hidden;
      padding-left: 8px;
      text-overflow: ellipsis;
      white-space: nowrap; }
  .select2-container .select2-search--inline {
    float: left; }
    .select2-container .select2-search--inline .select2-search__field {
      box-sizing: border-box;
      border: none;
      font-size: 100%;
      margin-top: 5px; }
      .select2-container .select2-search--inline .select2-search__field::-webkit-search-cancel-button {
        -webkit-appearance: none; }

.select2-dropdown {
  background-color: white;
  border: 1px solid #aaa;
  border-radius: 4px;
  box-sizing: border-box;
  display: block;
  position: absolute;
  left: -100000px;
  width: 100%;
  z-index: 1051; }

.select2-results {
  display: block; }

.select2-results__options {
  list-style: none;
  margin: 0;
  padding: 0; }

.select2-results__option {
  padding: 6px;
  user-select: none;
  -webkit-user-select: none; }
  .select2-results__option[aria-selected] {
    cursor: pointer; }

.select2-container--open .select2-dropdown {
  left: 0; }

.select2-container--open .select2-dropdown--above {
  border-bottom: none;
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0; }

.select2-container--open .select2-dropdown--below {
  border-top: none;
  border-top-left-radius: 0;
  border-top-right-radius: 0; }

.select2-search--dropdown {
  display: block;
  padding: 4px; }
  .select2-search--dropdown .select2-search__field {
    padding: 4px;
    width: 100%;
    box-sizing: border-box; }
    .select2-search--dropdown .select2-search__field::-webkit-search-cancel-button {
      -webkit-appearance: none; }
  .select2-search--dropdown.select2-search--hide {
    display: none; }

.select2-close-mask {
  border: 0;
  margin: 0;
  padding: 0;
  display: block;
  position: fixed;
  left: 0;
  top: 0;
  min-height: 100%;
  min-width: 100%;
  height: auto;
  width: auto;
  opacity: 0;
  z-index: 99;
  background-color: #fff;
  filter: alpha(opacity=0); }

.select2-container--default .select2-selection--single {
  background-color: #fff;
  border: 1px solid #aaa;
  border-radius: 4px; }
  .select2-container--default .select2-selection--single .select2-selection__rendered {
    color: #444;
    line-height: 28px; }
  .select2-container--default .select2-selection--single .select2-selection__clear {
    cursor: pointer;
    float: right;
    font-weight: bold; }
  .select2-container--default .select2-selection--single .select2-selection__placeholder {
    color: #999; }
  .select2-container--default .select2-selection--single .select2-selection__arrow {
    height: 26px;
    position: absolute;
    top: 1px;
    right: 1px;
    width: 20px; }
    .select2-container--default .select2-selection--single .select2-selection__arrow b {
      border-color: #888 transparent transparent transparent;
      border-style: solid;
      border-width: 5px 4px 0 4px;
      height: 0;
      left: 50%;
      margin-left: -4px;
      margin-top: -2px;
      position: absolute;
      top: 50%;
      width: 0; }
.select2-container--default[dir="rtl"] .select2-selection--single .select2-selection__clear {
  float: left; }
.select2-container--default[dir="rtl"] .select2-selection--single .select2-selection__arrow {
  left: 1px;
  right: auto; }
.select2-container--default.select2-container--disabled .select2-selection--single {
  background-color: #eee;
  cursor: default; }
  .select2-container--default.select2-container--disabled .select2-selection--single .select2-selection__clear {
    display: none; }
.select2-container--default.select2-container--open .select2-selection--single .select2-selection__arrow b {
  border-color: transparent transparent #888 transparent;
  border-width: 0 4px 5px 4px; }
.select2-container--default .select2-selection--multiple {
  background-color: white;
  border: 1px solid #aaa;
  border-radius: 4px;
  cursor: text; }
  .select2-container--default .select2-selection--multiple .select2-selection__rendered {
    box-sizing: border-box;
    list-style: none;
    margin: 0;
    padding: 0 5px;
    width: 100%; }
  .select2-container--default .select2-selection--multiple .select2-selection__placeholder {
    color: #999;
    margin-top: 5px;
    float: left; }
  .select2-container--default .select2-selection--multiple .select2-selection__clear {
    cursor: pointer;
    float: right;
    font-weight: bold;
    margin-top: 5px;
    margin-right: 10px; }
  .select2-container--default .select2-selection--multiple .select2-selection__choice {
    background-color: #e4e4e4;
    border: 1px solid #aaa;
    border-radius: 4px;
    cursor: default;
    float: left;
    margin-right: 5px;
    margin-top: 5px;
    padding: 0 5px; }
  .select2-container--default .select2-selection--multiple .select2-selection__choice__remove {
    color: #999;
    cursor: pointer;
    display: inline-block;
    font-weight: bold;
    margin-right: 2px; }
    .select2-container--default .select2-selection--multiple .select2-selection__choice__remove:hover {
      color: #333; }
.select2-container--default[dir="rtl"] .select2-selection--multiple .select2-selection__choice, .select2-container--default[dir="rtl"] .select2-selection--multiple .select2-selection__placeholder {
  float: right; }
.select2-container--default[dir="rtl"] .select2-selection--multiple .select2-selection__choice {
  margin-left: 5px;
  margin-right: auto; }
.select2-container--default[dir="rtl"] .select2-selection--multiple .select2-selection__choice__remove {
  margin-left: 2px;
  margin-right: auto; }
.select2-container--default.select2-container--focus .select2-selection--multiple {
  border: solid black 1px;
  outline: 0; }
.select2-container--default.select2-container--disabled .select2-selection--multiple {
  background-color: #eee;
  cursor: default; }
.select2-container--default.select2-container--disabled .select2-selection__choice__remove {
  display: none; }
.select2-container--default.select2-container--open.select2-container--above .select2-selection--single, .select2-container--default.select2-container--open.select2-container--above .select2-selection--multiple {
  border-top-left-radius: 0;
  border-top-right-radius: 0; }
.select2-container--default.select2-container--open.select2-container--below .select2-selection--single, .select2-container--default.select2-container--open.select2-container--below .select2-selection--multiple {
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0; }
.select2-container--default .select2-search--dropdown .select2-search__field {
  border: 1px solid #aaa; }
.select2-container--default .select2-search--inline .select2-search__field {
  background: transparent;
  border: none;
  outline: 0; }
.select2-container--default .select2-results > .select2-results__options {
  max-height: 200px;
  overflow-y: auto; }
.select2-container--default .select2-results__option[role=group] {
  padding: 0; }
.select2-container--default .select2-results__option[aria-disabled=true] {
  color: #999; }
.select2-container--default .select2-results__option[aria-selected=true] {
  background-color: #ddd; }
.select2-container--default .select2-results__option .select2-results__option {
  padding-left: 1em; }
  .select2-container--default .select2-results__option .select2-results__option .select2-results__group {
    padding-left: 0; }
  .select2-container--default .select2-results__option .select2-results__option .select2-results__option {
    margin-left: -1em;
    padding-left: 2em; }
    .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option {
      margin-left: -2em;
      padding-left: 3em; }
      .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option {
        margin-left: -3em;
        padding-left: 4em; }
        .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option {
          margin-left: -4em;
          padding-left: 5em; }
          .select2-container--default .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option .select2-results__option {
            margin-left: -5em;
            padding-left: 6em; }
.select2-container--default .select2-results__option--highlighted[aria-selected] {
  background-color: #5897fb;
  color: white; }
.select2-container--default .select2-results__group {
  cursor: default;
  display: block;
  padding: 6px; }

.select2-container--classic .select2-selection--single {
  background-color: #f6f6f6;
  border: 1px solid #aaa;
  border-radius: 4px;
  outline: 0;
  background-image: -webkit-linear-gradient(top, #ffffff 50%, #eeeeee 100%);
  background-image: -o-linear-gradient(top, #ffffff 50%, #eeeeee 100%);
  background-image: linear-gradient(to bottom, #ffffff 50%, #eeeeee 100%);
  background-repeat: repeat-x;
  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#eeeeee', GradientType=0); }
  .select2-container--classic .select2-selection--single:focus {
    border: 1px solid #5897fb; }
  .select2-container--classic .select2-selection--single .select2-selection__rendered {
    color: #444;
    line-height: 28px; }
  .select2-container--classic .select2-selection--single .select2-selection__clear {
    cursor: pointer;
    float: right;
    font-weight: bold;
    margin-right: 10px; }
  .select2-container--classic .select2-selection--single .select2-selection__placeholder {
    color: #999; }
  .select2-container--classic .select2-selection--single .select2-selection__arrow {
    background-color: #ddd;
    border: none;
    border-left: 1px solid #aaa;
    border-top-right-radius: 4px;
    border-bottom-right-radius: 4px;
    height: 26px;
    position: absolute;
    top: 1px;
    right: 1px;
    width: 20px;
    background-image: -webkit-linear-gradient(top, #eeeeee 50%, #cccccc 100%);
    background-image: -o-linear-gradient(top, #eeeeee 50%, #cccccc 100%);
    background-image: linear-gradient(to bottom, #eeeeee 50%, #cccccc 100%);
    background-repeat: repeat-x;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#eeeeee', endColorstr='#cccccc', GradientType=0); }
    .select2-container--classic .select2-selection--single .select2-selection__arrow b {
      border-color: #888 transparent transparent transparent;
      border-style: solid;
      border-width: 5px 4px 0 4px;
      height: 0;
      left: 50%;
      margin-left: -4px;
      margin-top: -2px;
      position: absolute;
      top: 50%;
      width: 0; }
.select2-container--classic[dir="rtl"] .select2-selection--single .select2-selection__clear {
  float: left; }
.select2-container--classic[dir="rtl"] .select2-selection--single .select2-selection__arrow {
  border: none;
  border-right: 1px solid #aaa;
  border-radius: 0;
  border-top-left-radius: 4px;
  border-bottom-left-radius: 4px;
  left: 1px;
  right: auto; }
.select2-container--classic.select2-container--open .select2-selection--single {
  border: 1px solid #5897fb; }
  .select2-container--classic.select2-container--open .select2-selection--single .select2-selection__arrow {
    background: transparent;
    border: none; }
    .select2-container--classic.select2-container--open .select2-selection--single .select2-selection__arrow b {
      border-color: transparent transparent #888 transparent;
      border-width: 0 4px 5px 4px; }
.select2-container--classic.select2-container--open.select2-container--above .select2-selection--single {
  border-top: none;
  border-top-left-radius: 0;
  border-top-right-radius: 0;
  background-image: -webkit-linear-gradient(top, #ffffff 0%, #eeeeee 50%);
  background-image: -o-linear-gradient(top, #ffffff 0%, #eeeeee 50%);
  background-image: linear-gradient(to bottom, #ffffff 0%, #eeeeee 50%);
  background-repeat: repeat-x;
  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#eeeeee', GradientType=0); }
.select2-container--classic.select2-container--open.select2-container--below .select2-selection--single {
  border-bottom: none;
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
  background-image: -webkit-linear-gradient(top, #eeeeee 50%, #ffffff 100%);
  background-image: -o-linear-gradient(top, #eeeeee 50%, #ffffff 100%);
  background-image: linear-gradient(to bottom, #eeeeee 50%, #ffffff 100%);
  background-repeat: repeat-x;
  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#eeeeee', endColorstr='#ffffff', GradientType=0); }
.select2-container--classic .select2-selection--multiple {
  background-color: white;
  border: 1px solid #aaa;
  border-radius: 4px;
  cursor: text;
  outline: 0; }
  .select2-container--classic .select2-selection--multiple:focus {
    border: 1px solid #5897fb; }
  .select2-container--classic .select2-selection--multiple .select2-selection__rendered {
    list-style: none;
    margin: 0;
    padding: 0 5px; }
  .select2-container--classic .select2-selection--multiple .select2-selection__clear {
    display: none; }
  .select2-container--classic .select2-selection--multiple .select2-selection__choice {
    background-color: #e4e4e4;
    border: 1px solid #aaa;
    border-radius: 4px;
    cursor: default;
    float: left;
    margin-right: 5px;
    margin-top: 5px;
    padding: 0 5px; }
  .select2-container--classic .select2-selection--multiple .select2-selection__choice__remove {
    color: #888;
    cursor: pointer;
    display: inline-block;
    font-weight: bold;
    margin-right: 2px; }
    .select2-container--classic .select2-selection--multiple .select2-selection__choice__remove:hover {
      color: #555; }
.select2-container--classic[dir="rtl"] .select2-selection--multiple .select2-selection__choice {
  float: right; }
.select2-container--classic[dir="rtl"] .select2-selection--multiple .select2-selection__choice {
  margin-left: 5px;
  margin-right: auto; }
.select2-container--classic[dir="rtl"] .select2-selection--multiple .select2-selection__choice__remove {
  margin-left: 2px;
  margin-right: auto; }
.select2-container--classic.select2-container--open .select2-selection--multiple {
  border: 1px solid #5897fb; }
.select2-container--classic.select2-container--open.select2-container--above .select2-selection--multiple {
  border-top: none;
  border-top-left-radius: 0;
  border-top-right-radius: 0; }
.select2-container--classic.select2-container--open.select2-container--below .select2-selection--multiple {
  border-bottom: none;
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0; }
.select2-container--classic .select2-search--dropdown .select2-search__field {
  border: 1px solid #aaa;
  outline: 0; }
.select2-container--classic .select2-search--inline .select2-search__field {
  outline: 0; }
.select2-container--classic .select2-dropdown {
  background-color: white;
  border: 1px solid transparent; }
.select2-container--classic .select2-dropdown--above {
  border-bottom: none; }
.select2-container--classic .select2-dropdown--below {
  border-top: none; }
.select2-container--classic .select2-results > .select2-results__options {
  max-height: 200px;
  overflow-y: auto; }
.select2-container--classic .select2-results__option[role=group] {
  padding: 0; }
.select2-container--classic .select2-results__option[aria-disabled=true] {
  color: grey; }
.select2-container--classic .select2-results__option--highlighted[aria-selected] {
  background-color: #3875d7;
  color: white; }
.select2-container--classic .select2-results__group {
  cursor: default;
  display: block;
  padding: 6px; }
.select2-container--classic.select2-container--open .select2-dropdown {
  border-color: #5897fb; }

<link href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.rawgit.com/select2/select2/master/dist/js/select2.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js"></script>

<select id="selectb">
  <option value="1">Select2</option>
  <option value="2">Chosen</option>
  <option value="4">selectize.js</option>
  <option value="6">typeahead.js</option>
</select>

Answer 4

当你在'select'标签上应用select2时，它隐藏了实际的标签并创建了自己的'input'标签，其下方带有'options'。 因此，当您将鼠标悬停在select2上时，实际上是将鼠标悬停在select2创建的“input”标记上，而不是在您编写的实际“select”标记上。要使标题可见，您必须在'input'标记中添加标题。 找到select2创建的'input'并在其上添加标题。

Answer 5

使用以下

<select id="daySelect">
<optgroup label="select your day">

Answer 6

尝试使用select2选项和方法：

<强> JS：

$("#daySelect").select2().on('select2:select', function(evt) {
  $(this).attr("title",$(this).val());
});

演示：http://jsfiddle.net/lotusgodkk/fyhsz9ra/1432/

Answer 7

let newOption = new Option("text", null, true, true); //.setAttribute("title", "test|title ll|gg");
            newOption.setAttribute("title", "test|title ll|gg");

然后当你有多个时，你可以把它放在一个 each 循环中。