EXTjs htmleditor 扩展图片上传在谷歌下不行

Question

最近要用到hemleditor的上传图片功能，看到网上有有一些扩展的例子，我就拿来用发现在谷歌下运行不了
HTMLEditor = Ext.extend(Ext.form.HtmlEditor, {
    addImage: function () {
        var editor = this;
        var imgform = new Ext.FormPanel({
            region: 'center',
            labelWidth: 55,
            frame: true,
            bodyStyle: 'padding:5px 5px 0',
            autoScroll: true,
            border: false,
            fileUpload: true,
            items: [{
                xtype: 'textfield',
                fieldLabel: '选择文件',
                name: 'userfile',
                inputType: 'file',
                allowBlank: false,
                blankText: '文件不能为空',
                height: 25,
                anchor: '90%'
            }],
            buttons: [{
                text: '上传',
                type: 'submit',
                handler: function () {
                    if (!imgform.form.isValid()) { return; }
                    imgform.form.submit({
                        waitMsg: '正在上传......',
                        url: 'Default.aspx',
                        success: function (form, action) {
                            var element = document.createElement("img");
                            element.src = action.result.fileURL;
                            if (Ext.isIE) {
                                editor.insertAtCursor(element.outerHTML);
                            } else {
                                var selection = editor.win.getSelection();
                                if (!selection.isCollapsed) {
                                    selection.deleteFromDocument();
                                }
                                debugger;
                                selection.getRangeAt(0).insertNode(element);
                            }
                            win.hide();
                        },
                        failure: function (form, action) {
                            form.reset();
                            if (action.failureType == Ext.form.Action.SERVER_INVALID)
                                Ext.MessageBox.alert('警告',
action.result.errors.msg);
                        }
                    });
                }
            }, {
                text: '关闭',
                type: 'submit',
                handler: function () {
                    win.close(this);
                }
            }]
        })        var win = new Ext.Window({
            title: "上传图片",
            width: 300,
            height: 200,
            modal: true,
            border: false,
            iconCls: "picture.png",
            layout: "fit",
            items: imgform        });
        win.show();
    },
    createToolbar: function (editor) {
        HTMLEditor.superclass.createToolbar.call(this, editor);
        this.tb.insertButton(16, {
            cls: "x-btn-icon",
            icon: "picture.png",
            handler: this.addImage,
            scope: this
        });
    }
});
Ext.reg('StarHtmleditor', HTMLEditor);
运行到
selection.getRangeAt(0).insertNode(element); 的时候 会出现WRONG_DOCUMENT_ERR: DOM Exception 4错误，请问这个问题该怎么解决extjs扩展