//	popup a action window in middle of screen.
function pop_act_win ( win_name, width, height )
{
	//	[in] width:		弹出窗口的宽度
	//	[in] height:	弹出窗口的高度
	
	var left = ( screen.width  - width  ) / 2;
	var top  = ( screen.height - height ) / 2;

	param = 'resizable=0, scrollbars=0, width=' + width + ', height=' + height + ', left=' + left + '; top=' + top;

	window.open ( '', win_name, param );
}