ReferenceError：未定义$

Question

我收到此错误消息，ReferenceError: $ is not defined这是我的标题。<link href="css/global-style.css" rel="stylesheet" type="text/css" media="screen"><link rel="stylesheet" type="text/css" media="screen" href="css/datepicker3.css"><script type="text/javascript" src="js/jquery.js"></script><script type="text/javascript" src="assets/bootstrap/js/bootstrap.min.js"></script><script type="text/javascript" src="js/bootstrap-datepicker.js"></script>以下是我的JavaScript代码<script type="text/javascript">$('#sandbox-container .input-daterange').datepicker({    startDate: "today",    calendarWeeks: true,    todayHighlight: true});</script>以下是HTML<div class="col-md-12" id="sandbox-container">    <label>Project Duration</label>    <div class="input-daterange input-group" id="datepicker">            <input type="text" class="input-md form-control" name="start" />            <span class="input-group-addon">to</span>            <input type="text" class="input-md form-control" name="end" />    </div></div>我想在输入标签上显示日期选择器。我正在使用Bootstrap V3.1。我正在使用此日期选择器