基于Bootstrap实现的下拉菜单手机端不能选择菜单项的原因附解决办法

<div class="input-group">
<span class="input-group-addon" id="sizing-addon2">本外地福利：</span>
<div class="btn-group">
<button type="button" class="btn btn-default dropdown-toggle" id="btnFuLi" name="btnFuLi" data-toggle="dropdown"
value="" aria-expanded="false">
请选择本外地福利… <span class="caret"></span>
</button>
<ul class="dropdown-menu" id="UiFuLi" role="menu">
<li><a title='1' href='#'>本地福利</a></li><li class='divider'></li>
<li><a title='2' href='#'>外地福利</a></li><li class='divider'></li> 
</ul>
<input id="txtFuLi" name="本外地福利"/>
</div>
</div>

DataBindFuLi: function () {
$("#UiFuLi li a").bind("click", function () {
var $this = $(this);
var $a = $this.parent().parent().prev()
var t = $this.text();
$a.val($this.attr('title'));
$('#txtFuLi').val($this.attr('title'));
$a.text($this.text());
$a.append("<span class='caret'>");
});
}

$this.parent().parent().prev()

$("#drpWorkType li a").bind("click", function () {
var $this = $(this);
//var $a = $this.parent().parent().prev()
$('#txtWorkType').val($this.attr('title'));
$('#btnWorkType').val($this.attr('title'));
$('#btnWorkType').text($this.text());
//$a.val($this.attr('title'));
//$a.text($this.text());
//$a.append("<span class='caret'>");
});