上传图片

var uploadFile = null;
var isFileValid = false;

function bindInputPictureEvent() {
    uploadFile = null;
    isFileValid = false;
    $('#carSearchImg').unbind().click(function () {
        $('#fileImage').trigger('click');
    });
    $("#fileImage").get(0).addEventListener("change", function (e) {
        var files = e.target.files || e.dataTransfer.files;
        if (files.length == 0) {
            return;
        }

        uploadFile = files[0];
        if (uploadFile) {
            var reader = new FileReader();
            reader.onload = function (e) {
                var newStr = uploadFile.name.split("").reverse().join("");
                var type = newStr.split(".")[0].split("").reverse().join("");
                if (uploadFile.type.indexOf("image") == 0) {
                    $('#carSearchImg').attr('src', e.target.result);
                    $('#carSearchImg').blowup({});
                    $('.upload_message_tip').hide();
                    //$('#carSearchImg').attr('rel', e.target.result);
                    //$("#carSearchImg").imagezoom();
                    //$('#bookImageContainer').show();
                    isFileValid = true;
                    uploadCarSearchImage(uploadFile);
                } else {
                    isFileValid = false;
                    //$('#bookImageContainer').hide();
                    $('#alertModal').find('.modal-body p').html('文件类型不符合');
                    $('#alertModal .btnBox').hide();
                    $('#alertModal').modal('show');
                }
            }
            reader.readAsDataURL(uploadFile);
        }

    }, false);

    var uploadCarSearchImage = function (image) {
        var self = this;
        var formdata = new FormData();
        formdata.append("file", image, encodeURI(image.name));
        //formdata.append("bookDetail", $.toJSON(book));
        var xhr = new XMLHttpRequest();

        // 进度
        xhr.upload.addEventListener("progress", function (e) {
            // 回调到外部
            //self.onProgress(image, e.loaded, e.total);
        }, false);
        // 完成
        xhr.addEventListener("load", function (e) {
            var response = e.currentTarget.response;
            var responseObj = JSON.parse(response);
            console.log(responseObj);
            var responseStatus = responseObj.status;
            if (responseStatus == "OK") {
                var hphm = responseObj.data.plateNum;
                var plateType = responseObj.data.plateType;
                var vehicleColor = responseObj.data.vehicleColor;
                var brandType = responseObj.data.brandType;
                $('#car_plate').val(hphm);
                $('#car_type').val(plateType);
                // 暂时隐藏，赋值之后查询不到一次识别数据
                // $('#car_color').val(vehicleColor);
                // $('#car_brand').val(brandType);
                // $('#plate_color').val(plateType2ColorMap[plateType]);
            }
            uploadFile = null;
            isFileValid = false;
            $("#fileImage").val("");
            return;
        }, false);
        // 错误
        xhr.addEventListener("error", function (e) {
            // 回调到外部
            $('#alertModal').find('.modal-body p').html('图片识别失败，请刷新页面重试！');
            $('#alertModal .btnBox').hide();
            $('#alertModal').modal('show');
        }, false);

        xhr.open("POST", "/car_image/image_data_service/vehicle_image/analyzing_uploading_file", true);
        //xhr.setRequestHeader("context-type","multipart/form-data;charset=utf-8");
        //xhr.setRequestHeader("content-type","application/json");
        xhr.send(formdata);
    }

}

 http://blog.okbase.net/jquery2000/archive/1296.html