function doPreferences()
{
  var target = document.forms[0].target;

  CenterWindow('Preferences','','520','450');
  document.forms[0].target = 'Preferences';
  doSubmitEx("PS","Preferences");

  document.forms[0].target = target;
}

function doClose()
{
  window.close();
}

function checkUncheckAll(chkboxE)
{
 var elements = chkboxE.form, z = 0;
 var formLength = document.forms[0].elements.length;
 var cnt;
 var element;
 
 for (cnt=0; cnt < formLength; cnt++)
 {
  element = document.forms[0].elements[cnt];
  if (element.type == "checkbox" && elements[z].name != "checkall")
  {
    elements[cnt].checked = chkboxE.checked;
  		
  }
 }
}