<!DOCTYPE html> <html> <body> <h1>Window 对象</h1> <h2>matchMedia() 方法</h2> <p id="demo"></p> <script> let text; if (window.matchMedia("(max-width: 700px)").matches) { text = "屏幕宽度小于或等于 700 像素。"; } else { text = "屏幕至少有 700 像素宽。"; } document.getElementById("demo").innerHTML = text; </script> </body> </html>