菜鸟教程在线编辑器

 
                <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
<style>
h1 {
  color: red;
  font-size: 50px;
}
</style>

<script>
function myFunction() {
  var s = document.styleSheets[0].rules[0].style;
  var ruleObj = s.parentRule;
  document.getElementById("demo").innerHTML = ruleObj.cssText;
}
</script> 
</head>
<body>

<h1>parentRule 属性</h1>

<p>parentRule 属性返回 CSSRule 对象，包含 CSS 选择器及声明的样式。 </p>

<button onclick="myFunction()">显示 CSS 样式</button>

<p id="demo"></p>

</body>
</html>
              