<script type="text/javascript">
                function setFontSize(value)
                {
            $id = 'omnie';
                    
                        document.getElementById($id).style.fontSize = value;
                        return false;
                }
        </script>

<a href="#" style="font-size: 12px; margin-right: 4px;" onclick="return setFontSize('80%');">A</a>
<a href="#" style="font-size: 14px; margin-right: 4px;" onclick="return setFontSize('100%');"><b>A</b></a>
<a href="#" style="font-size: 16px; margin-right: 20px;" onclick="return setFontSize('120%');"><b>A</b></a>