通过Ajax使用FormData对象无刷新上传文件

var oMyForm = new FormData();
oMyForm.append("username", "Groucho");
oMyForm.append("accountnum", 123456); 
oMyForm.append("file", $('#file')[0].files[0]);

$.ajax({
    url: '/Manage/UploadImg',
    type: 'POST',
    cache: false,
    data: oMyForm,
    processData: false,
    contentType: false,
    async: false,

error: function (request) {

},
success: function (data) {

}

});