CKEditor CDN( full )

<script src="//cdn.ckeditor.com/4.5.3/full/ckeditor.js"></script>
<textarea name="editor1"></textarea>
<style type="text/css">
.cke_button__mybutton_icon {
	display: none !important;
}
.cke_button__mybutton_label {
	display : inline !important;
}
</style>
<script>
editor = CKEDITOR.replace( 'editor1', {
	allowedContent : true,
	enterMode : CKEDITOR.ENTER_BR,
	enableTabKeyTools : true
} );
editor.on( 'pluginsLoaded', function(){
	editor.addCommand( 'svData', {
		modes : { source : 1,wysiwyg : 1 },
		exec : function( editor )   {
			localStorage["_save_ck_code"] = editor.getData();
		}
	}); 
	editor.ui.addToolbarGroup( "user" );
	editor.ui.addButton( 'mybutton',   {
		label : '入力内容を保存', command : 'svData', toolbar: 'user'
	} );
	var editor_code = localStorage["_save_ck_code"];
	if(typeof editor_code == 'string'){
		editor.setData(localStorage["_save_ck_code"]);
	}
});
</script>