I did not fully understand you question. But....
You can call $("#txtboxid").click() in you client side slider change event.
I hope I was able to solve your problem.
Watch my first article posted on codeproject and comment and vote:
http://www.codeproject.com/KB/HTML/speechinputapi.aspx
or http://blog.robinrizvi.info
Drop me a mail for any comments, suggestions or questions.
mail@robinrizvi.info