<html><body><h1 id="myH1">Element 对象</h1><h2>style 属性</h2><p id="myP" style="border-top: 5px solid red;">我的顶部边框的值是：</p><p id="demo"></p><script>let value = document.getElementById("myP").style.borderTop;document.getElementById("demo").innerHTML = value; </script></body></html>