disable button

With special thanks to thishttp://forum.dhtmlx.com/viewtopic.php?f=2&t=32415 post the button are creating, however I am unclear on how to get at the html to specifically disable a button. My GUI needs to have old buttons dimmed and new buttons enabled. How is this possible.

Please clarify, what do you mean by “new” and “old” buttons ?
Is row has some attribute which allows to distinguish them ?