XMLHttpRequest在Chrome和Firefox中返回不同的进度事件

Question

尝试克服Flash上​​传到服务器功能的可变缺陷 - 特别是在需要cookie时无法跟踪上传进度 - 我决定创建一个JavaScript函数来执行上传并跟踪上传进度事件。

这是：

window.you_animate = {
     objToString: function(obj) {
        var res = "{";
        for (var str in obj) {
            res += str +"=" + obj[str] + ",";
        }
        res += "}";
        return res;
    },

    upload: function(url, _files, _data, progressCb, successCb, errorCb) {
        alert("a,"+url);
        var fd = new FormData(),
            files = _files || [],
            data = _data || [],
            i;

        alert("b");
        for (i in data) {
            fd.append(i, data[i]);
        }

        alert("c");
        for (i = 0; i < files.length; i++) {
            var file = files[i];
            alert(i+"/"+files.length+" file= "+you_animate.objToString(file));
            var blob = file.file || new Blob(file.data, {
                    type: file.type
                });
            alert("blob= "+you_animate.objToString(blob));

            fd.append(file.name, blob);
        }
        alert("d");
        var ajax_opts = {
            type: 'POST',
            url: url,
            data: fd,
            headers: {},
            dataType: 'json',
            contentType: false,
            processData: false,
            xhr: function() {
                alert("1");
                var xhr = new window.XMLHttpRequest();

                if (xhr.upload) {
                    xhr.upload.addEventListener('progress', progressCb, false);
                }

                return xhr;
            },
            success: successCb || $.noop,
            error: errorCb || $.noop
        };
        alert("2");
        $.ajax(ajax_opts);
        alert("3");
    },

    uploadProgress: {},

    // => _data = base64 binary
    uploadFromFlash: function(url, _files, _data) {
        alert("0");
        var uploadProcess = {};
        var uploadProcessID = "id" + Math.floor(Math.random() * 1000000).toString();
        you_animate.uploadProgress[uploadProcessID] = uploadProcess;

        // workaround for Flash bug ("[]" in variable name)
        for (var str in _data) {
            _data["UploadCharacterForm["+str+"]"] = _data[str];
            delete _data[str];
        }

        alert("01");
        // base64 -> Blob-friendly stuff
        for (i = 0; i < _files.length; i++) {
            var file = _files[i];
            var binary = atob(file.data);
            var array = new Uint8Array(binary.length);
            for( var i = 0; i < binary.length; ++i ) { array[i] = binary.charCodeAt(i) }
            file.data = [array]; // NOTE : why "[array]" and not "array" ??
        }

        alert("02");
        you_animate.upload(url, _files, _data,
            function(progressEvent) {
                uploadProcess.progressEvent = progressEvent;
            },
            function(successEvent) {
                uploadProcess.successEvent = successEvent;
                uploadProcess = null;
            },
            function(errorEvent) {
                uploadProcess.errorEvent = errorEvent;
                uploadProcess = null;
            }
        );                  

        return uploadProcessID;
    },

    trackProcessID: function(id) {
        return you_animate.uploadProgress[id];
    },

    destroyProcessID: function(id) {
        delete you_animate.uploadProgress[id];
    },

    uploadForm: function(form, progressCb, successCb, errorCb) {
        var $form = $(form),
            action = $form.attr('action') + '?json';

        var data = $form.serializeArray().reduce(function(prev, curr){
            prev[curr.name] = curr.value; return prev;
        }, {} );

        var $files = $form.find('input[type=file]');
        var files = [];
        $files.each(function(index, node) {
            if (node.files[0]) {
                files.push({
                    name: node.name,
                    file: node.files[0]
                });
            }
        });

        you_animate.upload(action, files, data, progressCb, successCb, errorCb);
    }
};

问题1 ： Chrome和Firefox 之间的进度事件有所不同。第一个返回loaded＆amp; totalSize（在许多其他内容中），而Firefox返回loaded＆amp; total !!!

是否存在返回进度事件的规范？！

问题2 ：Internet Explorer 8在警报后立即崩溃（＆＃34; 0＆＃34;）！也许它不喜欢＆＃34; []＆＃34;在以下行中：

    _data["UploadCharacterForm["+str+"]"] = _data[str];

有什么关系吗？