Hi,
I can see you are trying to get the txtActo and txtActFromDate elements from javascript, but i think you are doing it in the wrong way. Can you please take a look at "view source" on that page? i think those are not the exactly names for the elements due to namespace issues.
Also the ".Text" property is not valid. It should be ".value" instead because you are trying to access those from javascript and not from the code behind.
Finally you cannot compare dates on that way, because, on that function you are comparing strings and not dates, you should first convert those string into dates and then compare.
Please check your function using these observations and let us now your results.
Thanks.