call a server-side event using **********

[C# Programming]

Hi Guys,
I have to implement a ********** code that will have to call a server side event(click event)
and do a post back.
Currently this is what i have....

function closeAndExit()
{
if ($("#dirty").val() == "true")
{
//Display the message
if(confirm(confirmExit()))
{
setDirty(false);//set the is dirty to false
__doPostBack("btnOk", "Click");//Post back the changes
Cancel_Clicked();//close the window
}else
{
return false;
}
}
else
{
Cancel_Clicked();
return false;
}
}

__doPostBack is what i am struggling with, can someone suggest something please.
Mninawa