protected function generateStyleAttribute()
    {
        // combine CSS classes
        $strClasses = '';
        foreach ($this->arrCssClasses as $strClass => $NULL) {
            if ($strClass != '')
                $strClass .= ' ';
            $strClasses .= $strClass;
        }
        $this->setAttribute('class', $strClasses);

        // combine CSS propertys
        $strPropertys = '';
        foreach ($this->arrCssPropertys as $strProperty => $strValue) {
            if ($strPropertys != '')
                $strPropertys .= ' ';
            $strPropertys .= $strProperty.': '.$strValue.';';
        }
        $this->setAttribute('style', $strPropertys);
    }