<!--
  function chkEmail(aObj){         
    if (aObj.value.length>0){
      i   = aObj.value.indexOf("@");
      j   = aObj.value.indexOf(".",i);
      k   = aObj.value.indexOf(",");
      kk  = aObj.value.indexOf(" ");
      jj  = aObj.value.lastIndexOf(".")+1;
      len = aObj.value.length;
      if ((i>0) && (j>(i+1)) && (k==-1) && (kk==-1) && (len-jj >=2) && (len-jj<=4))
        return true
      else{
        alert("Please check that you enter correct email address.\n"+aObj.value + " is invalid.");
        aObj.focus();
       return false;}}
    else{
      alert("Please enter an email address.");
      aObj.focus();
      return false;}}

 function chkSN(aObj){         
    if (aObj.value.length>0){
       i   = aObj.value.charAt(4);
      j   = aObj.value.charAt(0);
      len = aObj.value.length;
      if ((i==':') && ((j=='3') || (j=='2')) && (len >6))
        return true
      else{
        alert("Please check that you enter correct serial number.\n"+aObj.value + " \nis invalid.");
        aObj.focus();
       return false;}}
    else{
      alert("Please enter serial number.");
      aObj.focus();
      return false;}}

  function chkForm(aForm){
    return (chkEmail(aForm.Email));}

  function chkFormS(aForm){
    return (chkSN(aForm.sernum));}
    
  function LessonWindow(location,name,w,h) {
winparam='scrollbars=0,toolbar=0,location=0,directories=0,status=0,menubar=0,resizable=0,width=' + w + ',height=' + h;
win=window.open(location,name,winparam);
win.location.href = location;
}
//-->