为什么简码输出中的值“未定义” - tinyMCE

我已经成功地在WordPress编辑器中添加了一个微小的MCE按钮，用于添加列简码，除了我在弹出窗口中按"插入列"之外，它都可以正常工作。 输出未正确抓取所选值。 它将其输出到编辑器中：

[column size="undefined" last="undefined" margin="undefined" bottom="undefined"][/column]

以下是我到目前为止的脚本。 我错过了什么吗？

    (function() {
    tinymce.create('tinymce.plugins.ljshortcodes', {
        init : function(ed, url) {
            /* Column */   
            ed.addButton('column', {
                title : 'Add Column',
                text  : 'Column',
                onclick : function() {
                    tb_show( 'Column Shortcode', '#TB_inline?inlineId=column-form' );
                }
            });
        },
        createControl : function(n, cm) {
            return null;
        }
    });
    tinymce.PluginManager.add('ljshortcodes', tinymce.plugins.ljshortcodes);
    jQuery(function(){
        var form = jQuery('<div id="column-form"><div id="column-box" class="form-box">'
            <div class="option-row">'
                <div class="desc">'
                    <label for="column-size">Size</label>'
                </div>'
                <select name="size" id="column-size">'
                    <option value="half">One Half (1/2)</option>'
                    <option value="third">One Third (1/3)</option>'
                    <option value="twothirds">Two Thirds (2/3)</option>'
                    <option value="fourth">One Fourth (1/4)</option>'
                    <option value="threefourths">Three Fourths (3/4)</option>'
                    <option value="fifth">One Fifth (1/5)</option>'
                    <option value="twofifths">Two Fifths (2/5)</option>'
                    <option value="threefifths">Three Fifths (3/5)</option>'
                    <option value="fourfifths">Four Fifth (4/5)</option>'
                    <option value="full">Full (1/1)</option>'
                </select>'
            </div>'
            <div class="option-row">'
                <div class="desc">'
                    <label for="column-last">Last In Row?</label>'
                </div>'
                <select name="last" id="column-last">'
                    <option value="half">No</option>'
                    <option value="third">Yes</option>'
                </select>'
            </div>'
            <div class="option-row">'
                <div class="desc">'
                    <label for="column-margin">Remove All Margin?</label>'
                </div>'
                <select name="margin" id="column-margin">'
                    <option value="yes">No</option>'
                    <option value="no">Yes</option>'
                </select>'
            </div>'
            <div class="option-row">'
                <div class="desc">'
                    <label for="column-bottom">Remove Bottom Margin?</label>'
                </div>'
                <select name="bottom" id="column-bottom">'
                    <option value="yes">No</option>'
                    <option value="no">Yes</option>'
                </select>'
            </div>'
        </div>'
        <p class="submit">'
            <input type="button" id="column-submit" class="button-primary" value="Insert Column" name="submit" />'
        </p>'
        </div>');
        var column_form = form.find('#column-form');
        form.appendTo('body').hide();
        form.find('#column-submit').click(function(){
            var options = { 
                'size'      : '',
                'last'      : 'no',
                'margin'    : 'yes',
                'bottom'    : 'yes'
            };
            var shortcode = '[column';
            for( var index in options) {
                var value = column_form.find('#column-' + index).val();
                if ( value !== options[index] )
                    shortcode += ' ' + index + '="' + value + '"';
            }
            shortcode += '][/column]';
            tinyMCE.activeEditor.execCommand('mceInsertContent', 0, shortcode);
            tb_remove();
        });
    });
})();