I have faced a strange scenario that the onchange event for the check box in CRM 2011 is not working on my colleagues laptop but the same is working in my laptop as expected. Got shocked due to this behavior.
Later on searching in the net came to know that there are some more people in this shock and they have managed to come out of this with a solution.
Basically the problem was with the IE version which we both were using. I was using IE 10 and it worked properly. My colleague was using IE 8 in which it was not working.
In IE 8 the event will work only when the focus is taken out of the control. This is a kind of work around, but the problem is that this will not be accepted by some of the clients. 🙂
For that there is another work around. Please follow this blog for the same.
Also you can refer to the blog which I was referring to here.