Click a button on a webpage

Question

Hello,

I have a web page that contains a form and a button.
My application contains:
- Webbrowser (which loads and displays the web page)
- A button (which runs my task)

I make a success to fill the web form automatically by my application.
The problem is that it is impossible for me to find a code that allows my application to click on the button on the webpage.

The source code for the button (in the webpage):

 <INPUT onclick=submitQuickReplyForm(1) value="Envoyer la réponse" type=button><INPUT 
value=newreply type=hidden name=post><INPUT value=quick type=hidden 
name=format><INPUT value=1 type=hidden name=quickmode><INPUT value=25218769 
type=hidden name=topic>

Thanx.