function TrimString(sInString) {
  sInString = sInString.replace( /^\s+/g, "" );// strip leading
  return sInString.replace( /\s+$/g, "" );// strip trailing
}
function isEmailAddr (emailStr) {

/* The following variable tells the rest of the function whether or not
to verify that the address ends in a two-letter country or well-known
TLD.  1 means check it, 0 means don't. */

var checkTLD=1;

/* The following is the list of known TLDs that an e-mail address must end with. */

var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;

/* The following pattern is used to check if the entered e-mail address
fits the user@domain format.  It also is used to separate the username
from the domain. */

var emailPat=/^(.+)@(.+)$/;

/* The following string represents the pattern for matching all special
characters.  We don't want to allow special characters in the address. 
These characters include ( ) < > @ , ; : \ " . [ ] */

var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";

/* The following string represents the range of characters allowed in a 
username or domainname.  It really states which chars aren't allowed.*/

var validChars="\[^\\s" + specialChars + "\]";

/* The following pattern applies if the "user" is a quoted string (in
which case, there are no rules about which characters are allowed
and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
is a legal e-mail address. */

var quotedUser="(\"[^\"]*\")";

/* The following pattern applies for domains that are IP addresses,
rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
e-mail address. NOTE: The square brackets are required. */

var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;

/* The following string represents an atom (basically a series of non-special characters.) */

var atom=validChars + '+';

/* The following string represents one word in the typical username.
For example, in john.doe@somewhere.com, john and doe are words.
Basically, a word is either an atom or quoted string. */

var word="(" + atom + "|" + quotedUser + ")";

// The following pattern describes the structure of the user

var userPat=new RegExp("^" + word + "(\\." + word + ")*$");

/* The following pattern describes the structure of a normal symbolic
domain, as opposed to ipDomainPat, shown above. */

var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");

/* Finally, let's start trying to figure out if the supplied address is valid. */

/* Begin with the coarse pattern to simply break up user@domain into
different pieces that are easy to analyze. */

var matchArray=emailStr.match(emailPat);

if (matchArray==null) {

/* Too many/few @'s or something; basically, this address doesn't
even fit the general mould of a valid e-mail address. */

//alert("Email address seems incorrect (check @ and .'s)");
return false;
}
var user=matchArray[1];
var domain=matchArray[2];

// Start by checking that only basic ASCII characters are in the strings (0-127).

for (i=0; i<user.length; i++) {
if (user.charCodeAt(i)>127) {
//alert("Ths username contains invalid characters.");
return false;
   }
}
for (i=0; i<domain.length; i++) {
if (domain.charCodeAt(i)>127) {
//alert("Ths domain name contains invalid characters.");
return false;
   }
}

// See if "user" is valid 

if (user.match(userPat)==null) {

// user is not valid

//alert("The username doesn't seem to be valid.");
return false;
}

/* if the e-mail address is at an IP address (as opposed to a symbolic
host name) make sure the IP address is valid. */

var IPArray=domain.match(ipDomainPat);
if (IPArray!=null) {

// this is an IP address

for (var i=1;i<=4;i++) {
if (IPArray[i]>255) {
//alert("Destination IP address is invalid!");
return false;
   }
}
return true;
}

// Domain is symbolic name.  Check if it's valid.
 
var atomPat=new RegExp("^" + atom + "$");
var domArr=domain.split(".");
var len=domArr.length;
for (i=0;i<len;i++) {
if (domArr[i].search(atomPat)==-1) {
//alert("The domain name does not seem to be valid.");
return false;
   }
}

/* domain name seems valid, but now make sure that it ends in a
known top-level domain (like com, edu, gov) or a two-letter word,
representing country (uk, nl), and that there's a hostname preceding 
the domain or country. */

if (checkTLD && domArr[domArr.length-1].length!=2 && 
domArr[domArr.length-1].search(knownDomsPat)==-1) {
//alert("The address must end in a well-known domain or two letter " + "country.");
return false;
}

// Make sure there's a host name preceding the domain.

if (len<2) {
//alert("This address is missing a hostname!");
return false;
}

// If we've gotten this far, everything's valid!
return true;
}

/*
function isEmailAddr(email)
{
  var result = false;
  var theStr = new String(email);
  var index = theStr.indexOf(" ");
  if (index > 0)
  {
    return false;
  }
  index = theStr.indexOf(",");
  if (index > 0)
  {
    return false;
  }
  index = theStr.indexOf(";");
  if (index > 0)
  {
    return false;
  }
  index = theStr.indexOf(":");
  if (index > 0)
  {
    return false;
  }

  index = theStr.indexOf("@");
  if (index > 0)
  {
	var xindex = theStr.indexOf("@",index+1);
	if (xindex > 0)
	{
		return false;
	}
    var pindex = theStr.indexOf(".",index);
    if ((pindex > index+1) && (theStr.length > pindex+1))
	  result = true;
  }
  return result;
}
*/
function validRequired(formField,fieldLabel)
{
	var result = true;
	formField.value = TrimString(formField.value);
	if (formField.value == "")
	{
		alert('Please enter a value for the "' + fieldLabel +'" field.');
		formField.focus();
		result = false;
	}
	
	return result;
}

function allDigits(str)
{
	return inValidCharSet(str,"0123456789");
}

function inValidCharSet(str,charset)
{
	var result = true;

	// Note: doesn't use regular expressions to avoid early Mac browser bugs	
	for (var i=0;i<str.length;i++)
		if (charset.indexOf(str.substr(i,1))<0)
		{
			result = false;
			break;
		}
	
	return result;
}

function validEmail(formField,fieldLabel,required)
{
	var result = true;
	
	if (required && !validRequired(formField,fieldLabel))
		result = false;

	if (result && ((formField.value.length < 3) || !isEmailAddr(formField.value)) )
	{
		alert("Please enter a complete email address in the form: yourname@yourdomain.com");
		formField.focus();
		result = false;
	}
   
  return result;

}

function validNum(formField,fieldLabel,required)
{
	var result = true;

	if (required && !validRequired(formField,fieldLabel))
		result = false;
  
 	if (result)
 	{
 		if (!allDigits(formField.value))
 		{
 			alert('Please enter a number for the "' + fieldLabel +'" field.');
			formField.focus();		
			result = false;
		}
	} 
	
	return result;
}


function validInt(formField,fieldLabel,required)
{
	var result = true;

	if (required && !validRequired(formField,fieldLabel))
		result = false;
  
 	if (result)
 	{
 		var num = parseInt(formField.value,10);
 		if (isNaN(num))
 		{
 			alert('Please enter a number for the "' + fieldLabel +'" field.');
			formField.focus();		
			result = false;
		}
	} 
	
	return result;
}


function validDate(formField,fieldLabel,required)
{
	var result = true;

	if (required && !validRequired(formField,fieldLabel))
		result = false;
  
 	if (result)
 	{
 		var elems = formField.value.split("/");
 		
 		result = (elems.length == 3); // should be three components
		if (result == 0)
	    {
		  elems = formField.value.split("-");
		  result = (elems.length == 3);
		}
 		if (result)
 		{
 			var month = parseInt(elems[1],10);
  			var day = parseInt(elems[2],10);
 			var year = parseInt(elems[0],10);
			result = allDigits(elems[1]) && (month > 0) && (month < 13) &&
					 allDigits(elems[2]) && (day > 0) && (day < 32) &&
					 allDigits(elems[0]) && ((elems[2].length == 2) || (elems[2].length == 4));
 		}
 		
  		if (!result)
 		{
 			alert('Please enter a date in the format CCYY/MM/DD for the "' + fieldLabel +'" field.');
			formField.focus();		
		}
	} 
	
	return result;
}

// call function on page and customize the fields to be processed, copy and paste from below

/*
function validateForm(theForm)
{
	// Customize these calls for your form

	// Start ------->
	if (!validRequired(theForm.fullname,"Name"))
		return false;

	if (!validEmail(theForm.email,"Email Address",true))
		return false;

	if (!validDate(theForm.available,"Date Available",true))
		return false;

	if (!validNum(theForm.yearsexperience,"Years Experience",true))
		return false;
	// <--------- End
	return true;
}
  
*/