<html> <body> <p>本例使用 HTML DOM 将 "onloadstart" 事件分配给 video 元素。</p><video controls id="myVideo"> <source src="/i/photo/shanghai.mp4" type="video/mp4"> Your browser does not support HTML5 video.</video><script>document.getElementById("myVideo").onloadstart = function() {myFunction()};function myFunction() { alert("Starting to load video");}</script></body> </html>