jquery 选择器 E F-优快云博客

ancestor descendant

匹配所有的descendant 元素，其中descendant元素必须是ancestor 的子元素。返回匹配的结果集

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
                    "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
  <script src="http://code.jquery.com/jquery-latest.js"></script>
  
  <script>
  $(document).ready(function(){
    $("form input").css("border", "2px dotted blue");
  });
  </script>
  <style>
  body { font-size:14px; }
  form { border:2px green solid; padding:2px; margin:0; 
         background:#efe; }
  div { color:red; }
  fieldset { margin:1px; padding:3px; }
  </style>
</head>
<body>
  <form>
    <div>Form is surrounded by the green outline</div>
    <label>Child:</label>
    <input name="name" />
    <fieldset>
      <label>Grandchild:</label>
      <input name="newsletter" />
    </fieldset>
  </form>
  Sibling to form: <input name="none" />
</body>
</html>

$("form input").css("border", "2px dotted blue");

将匹配form元素下所有的input元素，并对满足条件的input元素加上样式：