function checkThisForm(formid, submitbuttonid, errors) {
  if (errors == '') {
    if (submitbuttonid != '') {eval('document.getElementById(\''+submitbuttonid+'\').disabled=true;');}
    document.getElementById(formid).submit();
    return true;
  } else {
    alert(errors);
    return false;
  }
}

function checkText(textboxid, displaytext) {
  var localerror = '';
  if(Trim(eval('document.getElementById(textboxid).value'))=='') {
    localerror =  '- '+displaytext+'\n';
  } else localerror = '';
  return localerror;
}

function checkNum(textboxid, displaytext) {
  var localerror = '';
  if(isNaN(eval('document.getElementById(textboxid).value'))) {
    localerror =  '- '+displaytext+'\n';
  } else localerror = '';
  return localerror;
}

function Trim(s) {
  while ((s.substring(0,1) == ' ') || (s.substring(0,1) == '\n') || (s.substring(0,1) == '\r')) {
    s = s.substring(1,s.length);
  }
  while ((s.substring(s.length-1,s.length) == ' ') || (s.substring(s.length-1,s.length) == '\n') || (s.substring(s.length-1,s.length) == '\r')) {
    s = s.substring(0,s.length-1);
  }
  return s;
}