<!DOCTYPE html> <html> <body> <h3>演示如何访问 VIDEO 元素</h3> <video id="myVideo" width="320" height="240" controls> <source src="/i/movie.mp4" type="video/mp4"> <source src="/i/movie.ogg" type="video/ogg"> Your browser does not support the video tag. </video> <p>请点击按钮来获得以秒计的视频时长。</p> <p id="demo"></p> <button onclick="myFunction()">试一下</button> <script> function myFunction() { var x = document.getElementById("myVideo").duration; document.getElementById("demo").innerHTML = x; } </script> </body> </html>