问如何添加ajax保存按钮，并将gif加载到CKeditor 4.2.1。[工作样例插件]

EN

config.extraPlugins = 'savebtn';//savebtn is the plugin's name
config.saveSubmitURL = 'http://server/link/to/post/';//link to serverside script to handle the post

CKEDITOR.plugins.add( 'savebtn', {
    icons: 'savebtn',
    init: function( editor ) {
        //add a new command to the editor. 
        //We give the command a name 'savecontent', 
        //so we can  reference it later. 
        editor.addCommand( 'savecontent', {
            //this is the business logic of our 'savecontent' command. 
            //this function gets executed when clicking the button.
            //you can change/replace the logic of this function  
            //according to your own needs.
            exec : function(editor){

                //get the text from ckeditor you want to save
                var data = editor.getData();

                //get the current url (optional)
                var page = document.URL;

                //path to the ajaxloader gif
                loading_icon=CKEDITOR.basePath+'plugins/savebtn/icons/loader.gif';

                //css style for setting the standard save icon. 
                //We need this when the request is completed.
                normal_icon=$('.cke_button__savebtn_icon').css('background-image');

                //replace the standard save icon with the ajaxloader icon. 
                //We do this with css.
                $('.cke_button__savebtn_icon').css("background-image", "url("+loading_icon+")");

                //Now we are ready to post to the server...
                $.ajax({
                    url: editor.config.saveSubmitURL,//the url to post at... configured in config.js
                    type: 'POST', 
                    data: {text: data, id: editor.name, page: page},//editor.name contains the id of the current editable html tag
                })
                .done(function(response) {
                    console.log("success");
                    alert('id: '+editor.name+' \nurl: '+page+' \ntext: '+data);

                })
                .fail(function() {
                    console.log("error");
                })
                .always(function() {
                    console.log("complete");
                    //set the button icon back to the original
                    $('.cke_button__savebtn_icon').css("background-image", normal_icon);
                });


            } 
    });


//add the save button to the toolbar. Mind that we declare command: 'savecontent'. 
//This way ckeditor knows what to do when clicking the button.

        editor.ui.addButton( 'savebtn', {
            label: 'Save',
            command: 'savecontent'
           // toolbar: 'insert'
        });


    }
});