Disable and enable grid

When you disable the grid using given code, it works. But if you click on the disabled grid it creates an error. So you need to try, catch that error.
Error comes from following function of grid.js

var dispatch=function(event,element){
var parts=element.id.split("/");
var tag=parts[0].split(".");
var obj=Active.System.all[tag[0]];
var type="_on"+event.type+"Event";
var i;
for(i=1;i<tag.length;i++){
var params=tag.split(":");
obj=obj.getTemplate.apply(obj,params)
}
var target=obj;
for(i=1;i<parts.length;i++){
target=target.getContent(parts[i])
}
if(window.HTMLElement){
window.event=event
}
/* ======= error ======== */
try{
target[type].call(obj,event);
}
catch(error){}
/* ======= error ========= */
if(window.HTMLElement){
window.event=null;
}
return;
};

I am not sure what you are trying to do, but just from the title of your post... I am doing it like this:

obj.setAttribute("enabled","true")

obj.setAttribute("disabled","true") ( grays out the grid )