function popup(url)
{
  var windowParameter = 'width=389,height=500,left=150,top=150';
  newWindow = window.open(url, '', windowParameter);
}

function big_popup(url, mywidth, myheight)
{
  if( !mywidth )
    mywidth = 650;
  if( !myheight )
    myheight = 450;

  var windowParameter = 'width=' + mywidth + ',height=' + myheight + ',left=100,top=100,resizable=yes,scrollbars=yes';
  newWindow = window.open(url, '', windowParameter);
}