index.html

<!DOCTYPE html>
<html>
  <head>
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" rel="stylesheet">
    <link href="https://rawgit.com/FezVrasta/bootstrap-material-design/master/dist/css/material-wfont.min.css" rel="stylesheet">
    <link href="https://rawgit.com/FezVrasta/bootstrap-material-design/master/dist/css/ripples.min.css" rel="stylesheet">

    <link href="jquery.dropdown.css" rel="stylesheet">
  </head>
  <body>

    <button>Click</button>

    <select multiple class="select form-control floating-label" placeholder="This is a placeholder">
      <option></option>
      <option selected>Foobar</option>
      <option selected>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option selected>Foobar</option>
      <option selected>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option selected>Foobar</option>
      <option selected>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option selected>Foobar</option>
      <option selected>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option selected>Foobar</option>
      <option selected>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
      <option>Foobar</option>
      <option>Is great</option>
    </select>

    <br><br><br>
    <br><br><br>
    <br><br><br>
    <select class="select" placeholder="This is a placeholder">
      <option></option>
      <option>Foobar</option>
      <option value="hi..." selected>Is great</option>
    </select>

    <br><br><br>

    <select id="multi" multiple>
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
    </select>


    <script src="https://code.jquery.com/jquery-2.1.1.min.js"></script>
    <script src="https://rawgit.com/FezVrasta/bootstrap-material-design/master/dist/js/material.min.js"></script>
    <script src="https://rawgit.com/FezVrasta/bootstrap-material-design/master/dist/js/ripples.min.js"></script>

    <script src="jquery.dropdown.js"></script>
    <script>
      $.material.init();

      $(document).ready(function() {
        $(".select").dropdown({"optionClass": "withripple"});
      });

      $().dropdown({autoinit: "select"});

      $("button").click(function() {
        $("body").append("<select class=select><option>hey</option><option>hey</option></select>");
      });

    </script>


    <style>
      body {
        width: 200px;
        margin: 100px;
      }
    </style>

  </body>
</html>