var teacherWindowOpen=0;
var teacherWindow;
function openTeacherWindow(teacherWeb)
{
  if(teacherWindowOpen==1 && !teacherWindow.closed)
  {
    teacherWindow.focus();
    teacherWindow.location = teacherWeb;
  }
  else
  {
    teacherWindow=window.open(teacherWeb, 'teacherwin','resizable=1,scrollbars=yes,width=500,height=400');
    teacherWindowOpen=1;
    teacherWindow.moveTo(0,0);
  }
}

var popWindowOpen=0;
var popWindow;
function popupWindow(url, width, height)
{
  if(popWindowOpen==1 && !popWindow.closed)
  {
    popWindow.focus();
    popWindow.location = url;
  }
  else
  {
    popWindow=window.open(url, 'popwin','resizable=1,scrollbars=yes,width=' + width + ',height=' + height);
    popWindowOpen=1;
    popWindow.moveTo(0,0);
  }
}