js音视频文件的时长

function getTimes() {
        var obj_file = document.getElementById("upload");
        var content = obj_file.files[0]
        console.log(content)
        //获取时长
        var url = URL.createObjectURL(content)
        var audioElement = new Audio(url);

        var duration;
        audioElement.addEventListener("loadedmetadata", function (_event) {
            duration = audioElement.duration;
            console.log(duration/60);
        });
    }