how to trigger updatepanel within a javascript function

Question

i have an updatepanel in my asp.net web page. I want to trigger the updatepanel within a javascript function insead of triggering with a button.
In order to do that, i used

Answer 1

I think if you put a hidden button inside the update panel and you can use the javascript to fire the click of this button, it will do what you want.

The button MUST be inside a hidden div and DON'T set visibile="false" because if you set it to false, the control will not render and the javascript will produce errors.