​x
 
<!DOCTYPE html>
<html>
<head>
<style>
h2::first-letter {
  font-size: 48px;
}
</style>
</head>
<body>
​
<h1>Window 对象</h1>
​
<h2 id="test" style="background-color:lightblue">
getComputedStyle() 方法
</h2>
​
<p>测试元素中 div::first-letter 的计算字体大小为：</p>
​
<p id="demo"></p>
​
<script>
const element = document.getElementById("test");
const cssObj = window.getComputedStyle(element, ":first-letter")
​
let size = cssObj.getPropertyValue("font-size");
document.getElementById("demo").innerHTML = size;
</script>
​
</body>
</html>
​