input上传mp3格式文件，预览并且获取时间

<input type="file" id="file" name="file" class="upfile" onchange="fileupload(this)"/>

<audio id="audio" controls="" style="display: none;"></audio>

    //附件展示
    $(function () {
            $("#file").change(function () {
                var objUrl = getObjectURL(this.files[0]);
                $("#audio").attr("src", objUrl);
                $("#audio")[0].play();
                $("#audio").show();
                getTime();
            });
        });
        <!--获取mp3文件的时间 兼容浏览器-->
        function getTime() {
            setTimeout(function () {
                var duration = $("#audio")[0].duration;
                if(isNaN(duration)){
                    getTime();
                }
                else{
                    console.info("该歌曲的总时间为："+$("#audio")[0].duration+"秒")
                }
            }, 10);
        }
        <!--把文件转换成可读URL-->
        function getObjectURL(file) {
            var url = null;
            if (window.createObjectURL != undefined) { // basic
                url = window.createObjectURL(file);
            } else if (window.URL != undefined) { // mozilla(firefox)
                url = window.URL.createObjectURL(file);
            } else if (window.webkitURL != undefined) { // webkit or chrome
                url = window.webkitURL.createObjectURL(file);
            }
            return url;
        }

//这里以下是对上传文件的验证
//音频文件上传
    function fileupload(file){
        if(file==null || file==undefined || file==''){
            $("#file").val("");
            window.top.customAlertTip("", "上传的附件不存在！", "warning");
            return;
        }
        //验证音频文件格式
        var b = fileValvoic(file);
        if(!b){
            $("#file").val("");
            return;
        }

    }
    //验证后缀
    function endWith(name,end){
        var filename = name.split(".");
        if(filename[filename.length-1]==end){
            return true;
        }else{
            return false;
        }
    }
    //验证音频格式和大小
    function fileValvoic(target){   

          var isIE = /msie/i.test(navigator.userAgent) && !window.opera;
        var fileSize = 0;
        var fileName = null;
        if (isIE && !target.files) {
          var filePath = target.value;
          var fileSystem = new ActiveXObject("Scripting.FileSystemObject");
          var file = fileSystem.GetFile (filePath);
          fileSize = file.Size;
          fileName = file.Name;
        }else{
             fileSize = target.files[0].size;
             fileName = target.files[0].name;
        }

        if(!endWith(fileName,"mp3")){
            window.top.customAlertTip("", "上传的附件不是mp3格式！", "warning");
            return false;
        }

        var size = fileSize / 1024 / 1024;
        if(size>10){
            window.top.customAlertTip("", "附件大小超过10M！", "warning");
             return false;
        }else{
            return true;
        }
    }