小米4，android版本4.4.4 上传文件取不到后缀

document.getElementById('fileInput').addEventListener('change', function(event) {  
                var file = $("#fileInput").get(0).files[0];  
                if(!file) {  
                    return;  
                }  
                var src = this.value;  
                var ext = src.slice(src.lastIndexOf(".") + 1).toLowerCase();  
                if(uploadType.indexOf(ext) != -1) {  
                    $("#fileType").val(file.name);  
                    UploadFile(file)  
                } else {  
                    mui.toast(elibraryTips.uploadType + " " + uploadType + " " + elibraryTips.files);  
                }  
            }, false);

UploadFile 是H5+的方法，就不贴了

打印 src的数据 :{"webkitRelativePath":"","lastModifiedDate":"2018-11-23T02:16:47.000Z","name":"26720","type":"","size":1091573}

求解。。。。。