fileuploader-custom.js

            // to cancel request set src to something else
            // we use src="javascript:false;" because it doesn't
            // trigger ie6 prompt on https
            iframe.setAttribute('src', 'javascript:false;');

            qq.remove(iframe);
        }
    },
    _upload: function(id, params){
        var input = this._inputs[id];

        if (!input){
            throw new Error('file with passed id was not added, or already uploaded or cancelled');
        }

        var fileName = this.getName(id);

        var iframe = this._createIframe(id);
        var form = this._createForm(iframe, params);
        form.appendChild(input);
        $(form).append($('<input type="hidden" name="authenticity_token" value="'+$("meta[name='csrf-token']").attr("content")+'"/>'));

        var self = this;
        this._attachLoadEvent(iframe, function(){
            self.log('iframe loaded');

            var response = self._getIframeContentJSON(iframe);

            self._options.onComplete(id, fileName, response);
            self._dequeue(id);

            delete self._inputs[id];
            // timeout added to fix busy state in FF3.6
            setTimeout(function(){
                qq.remove(iframe);
            }, 1);
        });

        form.submit();
        qq.remove(form);

        return id;
    },
    _attachLoadEvent: function(iframe, callback){
        qq.attach(iframe, 'load', function(){
            // when we remove iframe from dom
            // the request stops, but in IE load
            // event fires
            if (!iframe.parentNode){
                return;
            }

            // fixing Opera 10.53
            if (iframe.contentDocument &&
                iframe.contentDocument.body &&
                iframe.contentDocument.body.innerHTML == "false"){
                // In Opera event is fired second time
                // when body.innerHTML changed from false
                // to server response approx. after 1 sec
                // when we upload file with iframe
                return;
            }

            callback();
        });
    },
    /**
     * Returns json object received by iframe from server.
     */
    _getIframeContentJSON: function(iframe){
        // iframe.contentWindow.document - for IE<7
        var doc = iframe.contentDocument ? iframe.contentDocument: iframe.contentWindow.document,
            response;

        this.log("converting iframe's innerHTML to JSON");
        this.log("innerHTML = " + doc.body.innerHTML);

        try {
            response = eval("(" + doc.body.innerHTML + ")");
        } catch(err){
            response = {};
        }

        return response;
    },
    /**
     * Creates iframe with unique name
     */
    _createIframe: function(id){
        // We can't use following code as the name attribute
        // won't be properly registered in IE6, and new window
        // on form submit will open
        // var iframe = document.createElement('iframe');
        // iframe.setAttribute('name', id);

        var iframe = qq.toElement('<iframe src="javascript:false;" name="' + id + '" />');
        // src="javascript:false;" removes ie6 prompt on https

        iframe.setAttribute('id', id);

        iframe.style.display = 'none';
        document.body.appendChild(iframe);

        return iframe;
    },
    /**
     * Creates form, that will be submitted to iframe
     */
    _createForm: function(iframe, params){
        // We can't use the following code in IE6
        // var form = document.createElement('form');
        // form.setAttribute('method', 'post');
        // form.setAttribute('enctype', 'multipart/form-data');
        // Because in this case file won't be attached to request
        var form = qq.toElement('<form method="post" enctype="multipart/form-data"></form>');

        var queryString = qq.obj2url(params, this._options.action);

        form.setAttribute('action', queryString);
        form.setAttribute('target', iframe.name);
        form.style.display = 'none';
        document.body.appendChild(form);

        return form;
    }
});

/**
 * Class for uploading files using xhr
 * @inherits qq.UploadHandlerAbstract
 */
qq.UploadHandlerXhr = function(o){
    qq.UploadHandlerAbstract.apply(this, arguments);

    this._files = [];
    this._xhrs = [];

    // current loaded size in bytes for each file
    this._loaded = [];
};

// static method
qq.UploadHandlerXhr.isSupported = function(){
    var input = document.createElement('input');
    input.type = 'file';

    return (
        'multiple' in input &&
        typeof File != "undefined" &&
        typeof (new XMLHttpRequest()).upload != "undefined" );
};

// @inherits qq.UploadHandlerAbstract
qq.extend(qq.UploadHandlerXhr.prototype, qq.UploadHandlerAbstract.prototype)

qq.extend(qq.UploadHandlerXhr.prototype, {
    /**
     * Adds file to the queue
     * Returns id to use with upload, cancel
     **/
    add: function(file){
        if (!(file instanceof File)){
            throw new Error('Passed obj in not a File (in qq.UploadHandlerXhr)');
        }

        return this._files.push(file) - 1;
    },
    getName: function(id){
        var file = this._files[id];
        // fix missing name in Safari 4
        return file.fileName != null ? file.fileName : file.name;
    },
    getSize: function(id){
        var file = this._files[id];
        return file.fileSize != null ? file.fileSize : file.size;
    },
    /**
     * Returns uploaded bytes for file identified by id
     */
    getLoaded: function(id){
        return this._loaded[id] || 0;
    },
    /**
     * Sends the file identified by id and additional query params to the server
     * @param {Object} params name-value string pairs
     */
    _upload: function(id, params){
        var file = this._files[id],
            name = this.getName(id),
            size = this.getSize(id);

        this._loaded[id] = 0;

        var xhr = this._xhrs[id] = new XMLHttpRequest();
        var self = this;

        xhr.upload.onprogress = function(e){
            if (e.lengthComputable){
                self._loaded[id] = e.loaded;
                self._options.onProgress(id, name, e.loaded, e.total);
            }
        };

        xhr.onreadystatechange = function(){
            if (xhr.readyState == 4){
                self._onComplete(id, xhr);
            }
        };

        // build query string
        params = params || {};
        params['qqfile'] = name;
        var queryString = qq.obj2url(params, this._options.action);

        xhr.open("POST", queryString, true);
        xhr.setRequestHeader("X-Requested-With", "XMLHttpRequest");
        xhr.setRequestHeader("X-File-Name", encodeURIComponent(name));
        xhr.setRequestHeader("Content-Type", "application/octet-stream");
        xhr.setRequestHeader("X-CSRF-Token", $("meta[name='csrf-token']").attr("content"));
        xhr.setRequestHeader("Accept", "application/json");
        xhr.send(file);
    },
    _onComplete: function(id, xhr){
        // the request was aborted/cancelled
        if (!this._files[id]) return;

        var name = this.getName(id);
        var size = this.getSize(id);

        this._options.onProgress(id, name, size, size);

        if (xhr.status == 200){
            this.log("xhr - server response received");
            this.log("responseText = " + xhr.responseText);

            var response;

            try {
                response = eval("(" + xhr.responseText + ")");
            } catch(err){
                response = {};
            }

            this._completed_files.push({file: this._files[id], response: response});
            this._options.onComplete(id, name, response);

        } else {
            this._completed_files.push({file: this._files[id], response: {}});
            this._options.onComplete(id, name, {});
        }

        this._files[id] = null;
        this._xhrs[id] = null;
        this._dequeue(id);
    },
    _cancel: function(id){
        this._options.onCancel(id, this.getName(id));

        this._files[id] = null;

        if (this._xhrs[id]){
            this._xhrs[id].abort();
            this._xhrs[id] = null;
        }
    }
});
// @license-end