<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="http://apps.bdimg.com/libs/jquerymobile/1.4.5/jquery.mobile-1.4.5.min.css">
<script src="http://apps.bdimg.com/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="http://apps.bdimg.com/libs/jquerymobile/1.4.5/jquery.mobile-1.4.5.min.js"></script>
</head>
<body>

<div data-role="page">
  <div data-role="header">
  <h1>复选框</h1>
  </div>

  <div data-role="main" class="ui-content">
    <form method="post" action="demoform.php">
      <fieldset data-role="controlgroup">
        <legend>请选择您喜爱的颜色：</legend>
          <label for="red">红色</label>
          <input type="checkbox" name="favcolor" id="red" value="red">
          <label for="green">绿色</label>
          <input type="checkbox" name="favcolor" id="green" value="green">
          <label for="blue">蓝色</label>
          <input type="checkbox" name="favcolor" id="blue" value="blue">  
      </fieldset>
      <input type="button" id="btn" data-inline="true" value="提交">
    </form>
  </div>
</div>
    <script>
    $("#btn").on("click",function(){

      var vals=$("input[name='favcolor']:checked");

//这里的vals就是选中的集合 进行遍历就可以取出来

        alert(vals.length);
    });
    </script>
</body>
</html>