多选下拉框（select 下拉多选）

方法一：使用multiple-select.js和multiple-select .css实现

HTML代码：

js代码：

　　$('#checkedLevel').multipleSelect({
　　　　addTitle: true, //鼠标点悬停在下拉框时是否显示被选中的值
　　　　selectAll: false, //是否显示全部复选框，默认显示
　　　　name: "质控级别",
　　　　selectAllText: "选择全部", //选择全部的复选框的text值
　　　　allSelected: "全部", //全部选中后显示的值
　　　　//delimiter: ', ', //多个值直接的间隔符，默认是逗号
　　　　placeholder: "质控级别" //不选择时下拉框显示的内容
　　});

//设置默认选中:其中数组中多个值用逗号分隔，值是option的value
　　$("#checkedLevel").multipleSelect('setSelects', [1001,1002]);
设置选中后关闭下拉框：
$('#selectJcjb').multipleSelect("close");//其他的方法，可到js中去查看方法名，根据实际情况进行调用。

参照网址：http://wenzhixin.net.cn/p/multiple-select/docs/index.html?locale=zh_CN#with-optgroups1

　　　　　https://www.jqueryscript.net/form/jQuery-Plugin-For-Selecting-Multiple-Elements-Multiple-Select.html

　　　　 http://www.jq22.com/yanshi2604

　　　　 http://www.jq22.com/jquery-info2604

　　　　 http://www.jq22.com/jquery-info20898?tdsourcetag=s_pcqq_aiomsg

提示：也可以使用bootstrap.multiselect实现，参照网址：http://davidstutz.de/bootstrap-multiselect/

原文：https://blog.csdn.net/shunhua19881987/article/details/81354122

方法二：
参考网址：http://www.17sucai.com/pins/31871.html

　　　　 https://blog.csdn.net/haibo0668/article/details/79774558

方法三：

效果展示：

HTML代码：

用法：

$(function () {

    $("#organId").fSelect();
});

css文件：

.fs-wrap {
    position: relative;
    display: inline-block;
     200px;
    font-size: 12px;
    line-height: 1;
}

.fs-label-wrap {
    position: relative;
    border: 1px solid #ddd;
    cursor: default;
}

.fs-label-wrap,
.fs-dropdown {
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.fs-label-wrap .fs-label {
    padding: 4px 22px 4px 8px;
    text-overflow: ellipsis;
    white-space: nowrap;
    overflow: hidden;
}

.fs-arrow {
     0;
    height: 0;
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-top: 6px solid #000;
    position: absolute;
    top: 0;
    right: 5px;
    bottom: 0;
    margin: auto;
}

.fs-dropdown {
    position: absolute;
    background-color: #fff;
    border: 1px solid #ccc;
    margin-top: 5px;
     100%;
    z-index: 1000;
}

.fs-dropdown .fs-options {
    max-height: 200px;
    overflow: auto;
}

.fs-search input {
     100%;
    padding: 2px 4px;
    border: 0;
}

.fs-option,
.fs-search,
.fs-optgroup-label {
    padding: 6px 8px;
    border-bottom: 1px solid #eee;
    cursor: default;
}

.fs-option {
    cursor: pointer;
}

.fs-option.hl {
    background-color: #f5f5f5;
}

.fs-wrap.multiple .fs-option {
    position: relative;
    padding-left: 30px;
}

.fs-wrap.multiple .fs-checkbox {
    position: absolute;
    display: block;
     30px;
    top: 0;
    left: 0;
    bottom: 0;
}

.fs-wrap.multiple .fs-option .fs-checkbox i {
    position: absolute;
    margin: auto;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
     14px;
    height: 14px;
    border: 1px solid #aeaeae;
    border-radius: 2px;
    background-color: #fff;
}

.fs-wrap.multiple .fs-option.selected .fs-checkbox i {
    background-color: rgb(17, 169, 17);
    border-color: transparent;
    background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAgAAAAGCAYAAAD+Bd/7AAAABHNCSVQICAgIfAhkiAAAAAlwSFlzAAALEgAACxIB0t1+/AAAABx0RVh0U29mdHdhcmUAQWRvYmUgRmlyZXdvcmtzIENTNXG14zYAAABMSURBVAiZfc0xDkAAFIPhd2Kr1WRjcAExuIgzGUTIZ/AkImjSofnbNBAfHvzAHjOKNzhiQ42IDFXCDivaaxAJd0xYshT3QqBxqnxeHvhunpu23xnmAAAAAElFTkSuQmCC');
    background-repeat: no-repeat;
    background-position: center;
}

.fs-wrap .fs-option:hover {
    background-color: #f5f5f5;
}

.fs-optgroup-label {
    font-weight: bold;
}

.hidden {
    display: none;
}


/*根据本项目自定义修改*/
.visibility-hidden{
    display:block;
    visibility: hidden;
    position:absolute;
    top:0;
}
.deptWrap,.fs-wrap,.fs-label-wrap{
    100%;
    height:30px;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}
.fs-wrap{position:relative}
.fs-label-wrap .fs-label{
    padding: 0;
    height: 30px;
    line-height: 30px;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
    padding-left:6px;
    padding-right:10px;
}
.btnFixed{
    height:28px;
    text-align:center;
}
.btnFixed>.buttonDefault{
     60px;
    height: 24px;
    background: rgb(86, 148, 254);
    border: none;
    margin-left: 10px;
    color: #fff;
    margin-top: 2px;
    border-radius: 4px;
}
.btnFixed>.buttonDefault:hover{
    background: rgb(181, 226, 254);
    color: #4284f5;
}
.fs-search{padding:2px 8px;}
.fs-dropdown{
    margin-top: 0px;
    box-shadow: 4px 4px 4px #ddd;
}
.fs-wrap.multiple .fs-option.selected .fs-checkbox i{
    background-color: rgb(86, 148, 254);
}

js文件：

(function($) {

    $.fn.fSelect = function(options) {

        if (typeof options == 'string' ) {
            var settings = options;
        }
        else {
            //默认配置项
            var settings = $.extend({
                placeholder:  ' ===请选择=== ',//占位符，默认显示什么
                numDisplayed: 10,//设置页面上可以显示几个选项（超出这个数量将会显示选择了n项）
                overflowText: '选择了{n}项',//超出这个数量将会显示"选择了n项"
                searchText: '搜索',//搜索框中占位符显示什么字
                showSearch: true//是否显示搜索框
            }, options);
        }


        /**
         * Constructor
         */
        function fSelect(select, settings) {
            this.$select = $(select);
            this.settings = settings;
            this.create();
        }


        /**
         * Prototype class
         */
        fSelect.prototype = {
            create: function() {
                var multiple = this.$select.is('[multiple]') ? ' multiple' : '';
                this.$select.wrap('<div class="fs-wrap' + multiple + '"></div>');
                this.$select.before('<div class="fs-label-wrap"><div class="fs-label">' + this.settings.placeholder + '</div><span class="fs-arrow"></span></div>');
                this.$select.before('<div class="fs-dropdown hidden"><div class="fs-options"></div></div>');
                // this.$select.addClass('hidden');
                this.$select.addClass('visibility-hidden');
                this.$wrap = this.$select.closest('.fs-wrap');
                //添加全选和清空按钮
                var BtnFixed = '<div class="btnFixed"><button class="buttonDefault" id="selectAllBtn" type="button">全选</button><button class="buttonDefault" id="clearAllBtn" type="button">清空</button></div>';
                this.$wrap.find('.fs-dropdown').append(BtnFixed);
                this.reload();
            },

            reload: function() {
                //如果设置显示搜索框，执行下面方法
                if (this.settings.showSearch) {
                    var search = '<div class="fs-search"><input type="search" placeholder="' + this.settings.searchText + '" /></div>';
                    this.$wrap.find('.fs-dropdown').prepend(search);
                }
                var choices = this.buildOptions(this.$select);
                //获取到所有option选项
                this.$wrap.find('.fs-options').append(choices);

                //选中当前已选的值
                var valArr = this.$select.val();
                // if(valArr.length){
                if(valArr){
                    var $fsOption = this.$wrap.find('.fs-option');
                    valArr.forEach(function(currentValue){
                        $fsOption.each(function(){
                            if(currentValue == $(this).attr('data-value')){
                                $(this).addClass("selected");
                            }
                        });
                    });
                }
                //获取到选中状态的选项
                this.reloadDropdownLabel();
            },

            destroy: function() {
                this.$wrap.find('.fs-label-wrap').remove();
                this.$wrap.find('.fs-dropdown').remove();
                // this.$select.unwrap().removeClass('hidden');
                this.$select.unwrap().removeClass('visibility-hidden');
            },
            //获取select的option选项，并赋值到插件自定义的每一选项div里
            buildOptions: function($element) {
                var $this = this;

                var choices = '';
                $element.children().each(function(i, el) {
                    var $el = $(el);
                    //支持 optiongroup
                    if ('optgroup' == $el.prop('nodeName').toLowerCase()) {
                        choices += '<div class="fs-optgroup">';
                        choices += '<div class="fs-optgroup-label">' + $el.prop('label') + '</div>';
                        choices += $this.buildOptions($el);
                        choices += '</div>';
                    }
                    else {
                        var selected = $el.is('[selected]') ? ' selected' : '';
                        choices += '<div class="fs-option' + selected + '" data-value="' + $el.prop('value') + '"><span class="fs-checkbox"><i></i></span><div class="fs-option-label">' + $el.html() + '</div></div>';
                    }
                });

                return choices;
            },
            //每次加载时判断一下插件自定义的每一选项div哪些是选中状态，将选中状态对应的文字，push到一个数组labelText里，页面上显示出来的文字就是数组中获取到的文字
            reloadDropdownLabel: function() {
                var settings = this.settings;
                var labelText = [];

                this.$wrap.find('.fs-option.selected').each(function(i, el) {
                    labelText.push($(el).find('.fs-option-label').text());
                });

                if (labelText.length < 1) {
                    labelText = settings.placeholder;
                }
                else if (labelText.length > settings.numDisplayed) {
                    labelText = settings.overflowText.replace('{n}', labelText.length);
                }
                else {
                    labelText = labelText.join(', ');
                }

                this.$wrap.find('.fs-label').html(labelText);
                this.$wrap.find('.fs-label').attr("title",labelText);
                this.$select.change();
            }
        }


        /**
         * Loop through each matching element
         */
        return this.each(function() {
            var data = $(this).data('fSelect');

            if (!data) {
                data = new fSelect(this, settings);
                $(this).data('fSelect', data);
            }

            if (typeof settings == 'string') {
                data[settings]();
            }
        });
    }
    /**
     * Events
     */
    window.fSelect = {
        'active': null,
        'idx': -1
    };

    function setIndexes($wrap) {
        $wrap.find('.fs-option:not(.hidden)').each(function(i, el) {
            $(el).attr('data-index', i);
            $wrap.find('.fs-option').removeClass('hl');
        });
        $wrap.find('.fs-search input').focus();
        window.fSelect.idx = -1;
    }

    function setScroll($wrap) {
        var $container = $wrap.find('.fs-options');
        var $selected = $wrap.find('.fs-option.hl');

        var itemMin = $selected.offset().top + $container.scrollTop();
        var itemMax = itemMin + $selected.outerHeight();
        var containerMin = $container.offset().top + $container.scrollTop();
        var containerMax = containerMin + $container.outerHeight();

        if (itemMax > containerMax) { // scroll down
            var to = $container.scrollTop() + itemMax - containerMax;
            $container.scrollTop(to);
        }
        else if (itemMin < containerMin) { // scroll up
            var to = $container.scrollTop() - containerMin - itemMin;
            $container.scrollTop(to);
        }
    }
    //插件选项的点击事件
    $(document).on('click', '.fs-option', function() {
        var $wrap = $(this).closest('.fs-wrap');

        if ($wrap.hasClass('multiple')) {
            var selected = [];

            $(this).toggleClass('selected');
            $wrap.find('.fs-option.selected').each(function(i, el) {
                selected.push($(el).attr('data-value'));
            });
        }
        else {
            var selected = $(this).attr('data-value');
            $wrap.find('.fs-option').removeClass('selected');
            $(this).addClass('selected');
            $wrap.find('.fs-dropdown').hide();
        }
        $wrap.find('select').val(selected);
        $wrap.find('select').fSelect('reloadDropdownLabel');
    });

    $(document).on('keyup', '.fs-search input', function(e) {
        if (40 == e.which) {
            $(this).blur();
            return;
        }

        var $wrap = $(this).closest('.fs-wrap');
        var keywords = $(this).val();

        $wrap.find('.fs-option, .fs-optgroup-label').removeClass('hidden');

        if ('' != keywords) {
            $wrap.find('.fs-option').each(function() {
                var regex = new RegExp(keywords, 'gi');
                if (null === $(this).find('.fs-option-label').text().match(regex)) {
                    $(this).addClass('hidden');
                }
            });

            $wrap.find('.fs-optgroup-label').each(function() {
                var num_visible = $(this).closest('.fs-optgroup').find('.fs-option:not(.hidden)').length;
                if (num_visible < 1) {
                    $(this).addClass('hidden');
                }
            });
        }

        setIndexes($wrap);
    });
    //显示隐藏下拉选项
    $(document).on('click', function(e) {
        var $el = $(e.target);
        var $wrap = $el.closest('.fs-wrap');

        if (0 < $wrap.length) {
            if ($el.hasClass('fs-label')) {
                window.fSelect.active = $wrap;
                var is_hidden = $wrap.find('.fs-dropdown').hasClass('hidden');
                $('.fs-dropdown').addClass('hidden');

                if (is_hidden) {
                    $wrap.find('.fs-dropdown').removeClass('hidden');
                }
                else {
                    $wrap.find('.fs-dropdown').addClass('hidden');
                }

                setIndexes($wrap);
            }
        }
        else {
            $('.fs-dropdown').addClass('hidden');
            window.fSelect.active = null;
        }
    });

    $(document).on('keydown', function(e) {
        var $wrap = window.fSelect.active;

        if (null === $wrap) {
            return;
        }
        else if (38 == e.which) { // up
            e.preventDefault();

            $wrap.find('.fs-option').removeClass('hl');

            if (window.fSelect.idx > 0) {
                window.fSelect.idx--;
                $wrap.find('.fs-option[data-index=' + window.fSelect.idx + ']').addClass('hl');
                setScroll($wrap);
            }
            else {
                window.fSelect.idx = -1;
                $wrap.find('.fs-search input').focus();
            }
        }
        else if (40 == e.which) { // down
            e.preventDefault();

            var last_index = $wrap.find('.fs-option:last').attr('data-index');
            if (window.fSelect.idx < parseInt(last_index)) {
                window.fSelect.idx++;
                $wrap.find('.fs-option').removeClass('hl');
                $wrap.find('.fs-option[data-index=' + window.fSelect.idx + ']').addClass('hl');
                setScroll($wrap);
            }
        }
        else if (32 == e.which || 13 == e.which) { // space, enter
            $wrap.find('.fs-option.hl').click();
        }
        else if (27 == e.which) { // esc
            $('.fs-dropdown').addClass('hidden');
            window.fSelect.active = null;
        }
    });

    //=========================全选=====================================
    $(document).on('click','#selectAllBtn', function( ) {
        var $wrap = $(this).closest('.fs-wrap');

        if ($wrap.hasClass('multiple')) {
            var selected = [];

            $wrap.find(".fs-option").addClass('selected');
            $wrap.find('.fs-option.selected').each(function(i, el) {
                selected.push($(el).attr('data-value'));
            });
        }
        $wrap.find('select').val(selected);
        $wrap.find('select').fSelect('reloadDropdownLabel');
    });
    //=========================全不选/清空=====================================
    $(document).on('click','#clearAllBtn', function( ) {
        var $wrap = $(this).closest('.fs-wrap');

        if ($wrap.hasClass('multiple')) {
            var selected = [];

            $wrap.find(".fs-option").removeClass('selected');
            $wrap.find('.fs-option.selected').each(function(i, el) {
                selected.push($(el).attr('data-value'));
            });
        }
        $wrap.find('select').val(selected);
        $wrap.find('select').fSelect('reloadDropdownLabel');
    });

})(jQuery);

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原文地址：https://www.cnblogs.com/sherryweb/p/11057746.html