AngularJS - NVDA屏幕阅读器找不到子元素的名称

(function($){
	'use strict';
	
	const DataStatePropertyName = 'multiselect';
	const EventNamespace = '.multiselect';
	const PluginName = 'MultiSelect';
	
	var old = $.fn[PluginName];
	$.fn[PluginName] = plugin;
    $.fn[PluginName].Constructor = MultiSelect;
    $.fn[PluginName].noConflict = function () {
        $.fn[PluginName] = old;
        return this;
    };

    // Defaults
    $.fn[PluginName].defaults = {
        
    };
	
	// Static members
    $.fn[PluginName].EventNamespace = function () {
        return EventNamespace.replace(/^\./ig, '');
    };
    $.fn[PluginName].GetNamespacedEvents = function (eventsArray) {
        return getNamespacedEvents(eventsArray);
    };
	
	function getNamespacedEvents(eventsArray) {
        var event;
        var namespacedEvents = "";
        while (event = eventsArray.shift()) {
            namespacedEvents += event + EventNamespace + " ";
        }
        return namespacedEvents.replace(/\s+$/g, '');
    }
	
	function plugin(option) {
        this.each(function () {
            var $target = $(this);
            var multiSelect = $target.data(DataStatePropertyName);
            var options = (typeof option === typeof {} && option) || {};

            if (!multiSelect) {
                $target.data(DataStatePropertyName, multiSelect = new MultiSelect(this, options));
            }

            if (typeof option === typeof "") {
                if (!(option in multiSelect)) {
                    throw "MultiSelect does not contain a method named '" + option + "'";
                }
                return multiSelect[option]();
            }
        });
    }

    function MultiSelect(element, options) {
        this.$element = $(element);
        this.options = $.extend({}, $.fn[PluginName].defaults, options);
        this.destroyFns = [];
		
		this.$toggle = this.$element.children('.toggle');
		this.$toggle.attr('id', this.$element.attr('id') + 'multi-select-label');
		this.$backdrop = null;
		this.$allToggle = null;

        init.apply(this);
    }
	
	MultiSelect.prototype.open = open;
	MultiSelect.prototype.close = close;
	
	function init() {
		this.$element
		.addClass('multi-select')
		.attr('tabindex', 0);
		
        initAria.apply(this);
		initEvents.apply(this);
		updateLabel.apply(this);
		injectToggleAll.apply(this);
		
		this.destroyFns.push(function() {
			return '|'
		});
    }
	
	function injectToggleAll() {
		if(this.$allToggle && !this.$allToggle.parent()) {
			this.$allToggle = null;
		}
		
		this.$allToggle = $("<li><label><input type='checkbox'/>(all)</label><li>");
		
		this.$element
		.children('ul:first')
		.prepend(this.$allToggle);
	}
	
	function initAria() {
		this.$element
		.attr('role', 'combobox')
		.attr('aria-multiselect', true)
		.attr('aria-expanded', false)
		.attr('aria-haspopup', false)
		.attr('aria-labeledby', this.$element.attr("aria-labeledby") + " " + this.$toggle.attr('id'));
		
		this.$toggle
		.attr('aria-label', '');
	}
	
	function initEvents() {
		var that = this;
		this.$element
		.on(getNamespacedEvents(['click']), function($event) {	
			if($event.target !== that.$toggle[0] && !that.$toggle.has($event.target).length) {
				return;
			}			

			if($(this).hasClass('in')) {
				that.close();
			} else {
				that.open();
			}
		})
		.on(getNamespacedEvents(['keydown']), function($event) {
			var next = false;
			switch($event.keyCode) {
				case 13: 
					if($(this).hasClass('in')) {
						that.close();
					} else {
						that.open();
					}
					break;
				case 9:
					if($event.target !== that.$element[0]	) {
						$event.preventDefault();
					}
				case 27:
					that.close();
					break;
				case 40:
					next = true;
				case 38:
					var $items = $(this)
					.children("ul:first")
					.find(":input, button, a");

					var foundAt = $.inArray(document.activeElement, $items);				
					if(next && ++foundAt === $items.length) {
						foundAt = 0;
					} else if(!next && --foundAt < 0) {
						foundAt = $items.length - 1;
					}

					$($items[foundAt])
					.trigger('focus');
			}
		})
		.on(getNamespacedEvents(['focus']), 'a, button, :input', function() {
			$(this)
			.parents('li:last')
			.addClass('focused');
		})
		.on(getNamespacedEvents(['blur']), 'a, button, :input', function() {
			$(this)
			.parents('li:last')
			.removeClass('focused');
		})
		.on(getNamespacedEvents(['change']), ':checkbox', function() {
			if(that.$allToggle && $(this).is(that.$allToggle.find(':checkbox'))) {
				var allChecked = that.$allToggle
				.find(':checkbox')
				.prop("checked");
				
				that.$element
				.find(':checkbox')
				.not(that.$allToggle.find(":checkbox"))
				.each(function(){
					$(this).prop("checked", allChecked);
					$(this)
					.parents('li:last')
					.toggleClass('selected', $(this).prop('checked'));
				});
				
				updateLabel.apply(that);
				return;
			}
			
			$(this)
			.parents('li:last')
			.toggleClass('selected', $(this).prop('checked'));
			
			var checkboxes = that.$element
			.find(":checkbox")
			.not(that.$allToggle.find(":checkbox"))
			.filter(":checked");
			
			that.$allToggle.find(":checkbox").prop("checked", checkboxes.length === checkboxes.end().length);

			updateLabel.apply(that);
		})
		.on(getNamespacedEvents(['mouseover']), 'ul', function() {
			$(this)
			.children(".focused")
			.removeClass("focused");
		});
	}
	
	function updateLabel() {
		var pluralize = function(wordSingular, count) {
			if(count !== 1) {
				switch(true) {
					case /y$/.test(wordSingular):
						wordSingular = wordSingular.replace(/y$/, "ies");
					default:
						wordSingular = wordSingular + "s";
				}
			}			
			return wordSingular;
		}
		
		var $checkboxes = this.$element
		.find('ul :checkbox');
		
		var allCount = $checkboxes.length;
		var checkedCount = $checkboxes.filter(":checked").length
		var label = checkedCount + " " + pluralize("item", checkedCount) + " selected";
		
		this.$toggle
		.children("label")
		.text(checkedCount ? (checkedCount === allCount ? '(all)' : label) : 'Select a value');
		
		this.$element
		.children('ul')
		.attr("aria-label", label + " of " + allCount + " " + pluralize("item", allCount));
	}
	
	function ensureFocus() {
		this.$element
		.children("ul:first")
		.find(":input, button, a")
		.first()
		.trigger('focus')
		.end()
		.end()
		.find(":checked")
		.first()
		.trigger('focus');
	}
	
	function addBackdrop() {
		if(this.$backdrop) {
			return;
		}
		
		var that = this;
		this.$backdrop = $("<div class='multi-select-backdrop'/>");
		this.$element.append(this.$backdrop);
		
		this.$backdrop
		.on('click', function() {
			$(this)
			.off('click')
			.remove();
			
			that.$backdrop = null;			
			that.close();
		});
	}
	
	function open() {
		if(this.$element.hasClass('in')) {
			return;
		}

		this.$element
		.addClass('in');
		
		this.$element
		.attr('aria-expanded', true)
		.attr('aria-haspopup', true);

		addBackdrop.apply(this);
		//ensureFocus.apply(this);
	}
	
	function close() {
		this.$element
		.removeClass('in')
		.trigger('focus');
		
		this.$element
		.attr('aria-expanded', false)
		.attr('aria-haspopup', false);

		if(this.$backdrop) {
			this.$backdrop.trigger('click');
		}
	}	
})(jQuery);

$(document).ready(function(){
	$('#multi-select-plugin')
	.MultiSelect();
});

* {
  box-sizing: border-box;
}

.multi-select, .multi-select-plugin {
  display: inline-block;
  position: relative;
}
.multi-select > span, .multi-select-plugin > span {
  border: none;
  background: none;
  position: relative;
  padding: .25em .5em;
  padding-right: 1.5em;
  display: block;
  border: solid 1px #000;
  cursor: default;
}
.multi-select > span > .chevron, .multi-select-plugin > span > .chevron {
  display: inline-block;
  transform: rotate(-90deg) scale(1, 2) translate(-50%, 0);
  font-weight: bold;
  font-size: .75em;
  position: absolute;
  top: .2em;
  right: .75em;
}
.multi-select > ul, .multi-select-plugin > ul {
  position: absolute;
  list-style: none;
  padding: 0;
  margin: 0;
  left: 0;
  top: 100%;
  min-width: 100%;
  z-index: 1000;
  background: #fff;
  border: 1px solid rgba(0, 0, 0, 0.15);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.175);
  display: none;
  max-height: 320px;
  overflow-x: hidden;
  overflow-y: auto;
}
.multi-select > ul > li, .multi-select-plugin > ul > li {
  white-space: nowrap;
}
.multi-select > ul > li.selected > label, .multi-select-plugin > ul > li.selected > label {
  background-color: LightBlue;
}
.multi-select > ul > li.focused > label, .multi-select-plugin > ul > li.focused > label {
  background-color: DodgerBlue;
}
.multi-select > ul > li > label, .multi-select-plugin > ul > li > label {
  padding: .25em .5em;
  display: block;
}
.multi-select > ul > li > label:focus, .multi-select > ul > li > label:hover, .multi-select-plugin > ul > li > label:focus, .multi-select-plugin > ul > li > label:hover {
  background-color: DodgerBlue;
}
.multi-select.in > ul, .multi-select-plugin.in > ul {
  display: block;
}
.multi-select-backdrop, .multi-select-plugin-backdrop {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 900;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<label id="multi-select-plugin-label" style="display:block;">Multi Select</label>
<div id="multi-select-plugin" aria-labeledby="multi-select-plugin-label">
	<span class="toggle">
		<label>Select a value</label>
		<span class="chevron">&lt;</span>
	</span>
	<ul>
		<li>
			<label>
				<input type="checkbox" name="selected" value="0"/>
				Item 1
			</label>
		</li>
		<li>
			<label>
				<input type="checkbox" name="selected" value="1"/>
				Item 2
			</label>
		</li>
		<li>
			<label>
				<input type="checkbox" name="selected" value="2"/>
				Item 3
			</label>
		</li>
		<li>
			<label>
				<input type="checkbox" name="selected" value="3"/>
				Item 4
			</label>
		</li>
	</ul>
</div>