function enableScrolling()
{
  try
  {
    parent.document.getElementById("main_frame").scrolling="auto";
  }
  catch(e){}
  try
  {
    document.body.scroll = "auto";
  }
  catch(e){}
}
function disableScrolling()
{
  try
  {
    parent.document.getElementById("main_frame").scrolling="no"
  }
  catch(e){}
  try
  {
    document.body.scroll = "no";
  }
  catch(e){}
}