第一坑先引入jQuery ./引入

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

第一坑

    <script src="./bootstrap-3.3.7-dist/js/jQuery.js"></script>
    <script src="./bootstrap-3.3.7-dist/js/bootstrap.js"></script>
    <link rel="stylesheet" href="./bootstrap-3.3.7-dist/css/bootstrap.css">

先引入jQuery ./引入

</head>
<body>
<script>
    console.log($)

</script>
<div class="dropdown">
  <button class="btn btn-default dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="true">
    Dropdown <span class="caret"></span>
  </button>
  <ul class="dropdown-menu" aria-labelledby="dropdownMenu4">
    <li><a href="#">Regular link</a></li>
    <li class="disabled"><a href="#">Disabled link</a></li>
    <li role="separator" class="divider"></li>
    <li><a href="#">Another link</a></li>
  </ul>
</div>
</body>
</html>

第一坑 先引入jQuery ./引入

第一坑

先引入jQuery ./引入

第一坑先引入jQuery ./引入