function validateFieldMatch( field1, field2, custErr ) {
 if (field1.value != field2.value) {
  if (!custErr || custErr.length == 0) {
   return '-> ' + field1.name + ' and ' + field2.name + " do not match.\n";
  } else {
   return '-> ' + custErr + "\n";
  }
 } else {
  return '';
 }
}

function validateAllOrNone( fields, custErr ) {
 var at_least_one_present = 0;
 var at_least_one_missing = 0;
 for (i=0; i < fields.length; i++) {
  if (!fields[i] || fields[i].value.length == 0) {
   at_least_one_missing = 1;
  } else {
   at_least_one_present = 1;
  }
 }
 if (at_least_one_present && at_least_one_missing) {
  return '-> ' + custErr + "\n";
 } else {
  return '';
 }
}

function validateAtLeastOneChecked( frm, field_name, custErr ) {
 var checkboxes_checked = 0;
 for (i=0; i< frm.elements.length; i++) {
  if (frm.elements[i].name == field_name) {
   if (frm.elements[i].checked) {
    checkboxes_checked = 1;
   }
  }
 }
 if (checkboxes_checked == 0) {
   return '-> ' + custErr + "\n";
 } else {
  return '';
 }
}

function validateAtLeastOneCheckedGlobal( frm, custErr ) {
 var checkboxes_checked = 0;
 for (i=0; i< frm.elements.length; i++) {
  if (frm.elements[i].type == 'checkbox') {
   if (frm.elements[i].checked) {
    checkboxes_checked = 1;
   }
  }
 }
 if (checkboxes_checked == 0) {
   return '-> ' + custErr + "\n";
 } else {
  return '';
 }
}

function validateEmail(email) {
 var emailPat=/^(.+)@(.+)$/;
 var specialChars="\\(\\)<>@,;:\\\\\\\"\\.\\[\\]";
 var validChars="\[^\\s" + specialChars + "\]";
 var quotedUser="(\"[^\"]*\")";
 var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
 var atom=validChars + '+';
 var word="(" + atom + "|" + quotedUser + ")";
 var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
 var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
 var matchArray=email.match(emailPat);

 if (matchArray==null) {
  return false;
 }

 var user=matchArray[1];
 var domain=matchArray[2];

 if (user.match(userPat)==null) {
  return false;
 }

 var IPArray=domain.match(ipDomainPat);
 if (IPArray!=null) {
  for (var i=1;i<=4;i++) {
   if (IPArray[i]>255) {
    return false;
   }
  }
  return true;
 }

 var domainArray=domain.match(domainPat);
 if (domainArray==null) {
  return false;
 }

 var atomPat=new RegExp(atom,"g");
 var domArr=domain.match(atomPat);
 var len=domArr.length;
 if (domArr[domArr.length-1].length<2 || domArr[domArr.length-1].length>3) {
  return false;
 }

 if (len<2) {
  return false;
 }

 return true;
}

function validateData(strValidateStr,objValue,custErr) {
 var strErr = '';
 var epos = strValidateStr.search("=");
 var command  = "";
 var cmdvalue = "";
 if(epos >= 0) {
  command  = strValidateStr.substring(0,epos);
  cmdvalue = strValidateStr.substr(epos+1);
 } else {
  command = strValidateStr;
 }

 switch(command) {

 case "req": case "required": {
  if (eval(objValue.value.length) == 0) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name + " : Required Field.\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "maxlength":
 case "maxlen": {
  if (eval(objValue.value.length) >  eval(cmdvalue)) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name + " : "+cmdvalue+" characters maximum."
           + "\n       [Current length = " + objValue.value.length + " ].\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "minlength": 
 case "minlen": {
  if (eval(objValue.value.length) <  eval(cmdvalue)) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name + " : " + cmdvalue + " characters minimum."
           + "\n       [Current length = " + objValue.value.length + " ].\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "alnum":
 case "alphanumeric": {
  var charpos = objValue.value.search("[^A-Za-z0-9]");
  if (objValue.value.length > 0 &&  charpos >= 0) {
   if (!custErr || custErr.length == 0) {
    strErr = objValue.name+": Only alpha-numeric characters allowed."
           + "\n       [Error character position " + eval(charpos+1)+"].";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break; 
 }

 case "num": 
 case "numeric": {
  var charpos = objValue.value.search("[^0-9]");
  if (objValue.value.length > 0 &&  charpos >= 0) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name+": Only digits allowed "
           + "\n       [Error character position " + eval(charpos+1)+"].\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "alphabetic":
 case "alpha": {
  var charpos = objValue.value.search("[^A-Za-z]");
  if (objValue.value.length > 0 &&  charpos >= 0) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name+": Only alphabetic characters allowed"
           + "\n       [Error character position " + eval(charpos+1)+"].\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break; 
 }

 case "email": {
  if (!validateEmail(objValue.value,strErr)) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name+": Enter a valid Email address.\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "lt": 
 case "lessthan": {
  if (isNaN(objValue.value)) {
   strErr = strError + '-> ' + objValue.name+": Should be a number.\n";
  } else {
   if (eval(objValue.value) >=  eval(cmdvalue)) {
    if (!custErr || custErr.length == 0) {
     strErr = '-> ' + objValue.name
            + " : value should be less than "+ cmdvalue +".\n";
    } else {
     strErr = '-> ' + custErr + "\n";
    }
   }
  }
  break;
 }

 case "gt": 
 case "greaterthan": {
  if (isNaN(objValue.value)) {
   strErr = '-> ' + objValue.name+": Should be a number.\n";
  } else {
   if (eval(objValue.value) <=  eval(cmdvalue)) {
    if (!custErr || custErr.length == 0) {
     strErr = '-> ' + objValue.name
            + " : value should be greater than " + cmdvalue + ".\n";
    } else {
     strErr = '-> ' + custErr + "\n";
    }
   }
  }
  break;
 }

 case "regexp": {
  if (!objValue.value.match(cmdvalue))  {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name+": Invalid characters found.\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "notregexp": case "!regexp": {
  if (objValue.value.match(cmdvalue)) {
   if (!custErr || custErr.length == 0) {
    strErr = '-> ' + objValue.name+": Invalid characters found.\n";
   } else {
    strErr = '-> ' + custErr + "\n";
   }
  }
  break;
 }

 case "dontselect": {
  if (objValue.selectedIndex == null) {
   alert("BUG: dontselect command for non-select Item");
  } else {
   if (objValue.selectedIndex == eval(cmdvalue)) {
    if (!custErr || custErr.length == 0) {
     strErr = '-> ' + objValue.name+": Please Select one option.\n";
    } else {
     strErr = '-> ' + custErr + "\n";
    }
   }
  }
  break;
 }

 }
 return strErr;
}

function validateForm(objFrm,arrObjDesc) {
 var strErr = '';
 for(var itrobj=0; itrobj < arrObjDesc.length; itrobj++) {
  var strErr_element = '';
  if(objFrm.elements.length <= itrobj)  { 
   alert("BUG: Obj descriptor for a non existent form element"); 
   return false; 
  }
  for (var itrdesc=0; itrdesc < arrObjDesc[itrobj].length ;itrdesc++) {
   if (strErr_element != '') {
    break;
   }
   strErr_element = validateData( arrObjDesc[itrobj][itrdesc][0],
                                  objFrm[itrobj],
                                  arrObjDesc[itrobj][itrdesc][1] );
  }
  strErr = strErr + strErr_element;
 }
 return strErr;
}

//-- if using this method, you must specify the validation array
//-- in reverse order as well
function validateFormReverse(objFrm,arrObjDesc) {
 var strErr = '';
 for(var itrobj=0; itrobj < arrObjDesc.length; itrobj++) {
  var strErr_element = '';
  if(objFrm.elements.length <= itrobj)  { 
   alert("BUG: Obj descriptor for a non existent form element"); 
   return false; 
  }
  for (var itrdesc=0; itrdesc < arrObjDesc[itrobj].length ;itrdesc++) {
   if (strErr_element != '') {
    break;
   }
   strErr_element = validateData( arrObjDesc[itrobj][itrdesc][0],
                                  objFrm[objFrm.length-1-itrobj],
                                  arrObjDesc[itrobj][itrdesc][1] );
  }
  strErr = strErr + strErr_element;
 }
 return strErr;
}

function displayErrors( header, strErr ) {
 if ((strErr) && (strErr.length > 0)) {
  alert( header + "\n" + strErr );
  return true;
 } else {
  return false;
 }
}