<!DOCTYPE html> <html> <body> <h1>Element 对象</h1> <h2>isDefaultNamespace 属性</h2> <p>指定的命名空间是默认的吗?</p> <p id="demo"></p> <script> const element = document.documentElement; let answer = element.isDefaultNamespace("http://www.w3.org/1999/xhtml"); document.getElementById("demo").innerHTML = answer; </script> </body> </html>