代碼如下var video=$('.video-js');var allDuration=video[0].duration;var t2 = window.setInterval("checkLoading()",100);function checkLoading() { var allBuffered=video[0].buffered.end(0);    for(var i=0;i<video.length;i++){     allBuffered += video[0].buffered.end(0);    }    if(allBuffered >= allDuration){//緩存完    }else{        var num=parseInt(allDuration/allBuffered);        $(".loading .tips span").text(num);     }}第一個問題就是緩存的進度video[0].buffered.end(0)我的視頻是58.62s，但它好像緩存到17.92左右就一直不變了。第二個問題就是又是video[0].buffered.end(0)會報錯：(index):256 Uncaught DOMException: Failed to execute 'end' on 'TimeRanges': The index provided (0) is greater than or equal to the maximum bound (0).求解，謝謝！