Manual postback

[MS le Roux]

If you do a manual postback by calling __doPostBack in javascript, what happens to the value you send for the eventArgument argument? For example, suppose the following is called in javascript:

__doPostBack('Button1','Woof');

This causes a postback, and I want to extract the value "Woof". How/where do I do that, if it is even possible? (In Button1_Click, the only thing the EventArgs argument contains is something called Object, of type System.EventArgs.)