<video id="video" preload="auto">                                 <source src="./static/video/movie.ogg" type="video/ogg"> </video>                                                     下面是JS獲取duration和currentTime，前者是無窮大，后者報錯，沒有curretTime屬性var length = e.pageX - $('#progressWrap').offset().left;  var percent = length / progressWrap.offsetWidth;          playProgress.style.width =percent*410+ "px";              video.pause();                                            video.currentTime =Math.ceil( percent * video.duration);  video.play();                                             progressFlag = setInterval(getProgress, 60);