/* This function checks for a valid date */
function isValidDate(dateStr, format) {
   if (format == null) { format = "MDY"; }
   format = format.toUpperCase();
   if (format.length != 3) { format = "MDY"; }
   if ( (format.indexOf("M") == -1) || (format.indexOf("D") == -1) || (format.indexOf("Y") == -1) ) { format = "MDY"; }
   if (format.substring(0, 1) == "Y") // If the year is first
   { 
      var reg1 = /^\d{2}(\-|\/|\.)\d{1,2}\1\d{1,2}$/
      var reg2 = /^\d{4}(\-|\/|\.)\d{1,2}\1\d{1,2}$/
   } 
   else if (format.substring(1, 2) == "Y") // If the year is second
   { 
      var reg1 = /^\d{1,2}(\-|\/|\.)\d{2}\1\d{1,2}$/
      var reg2 = /^\d{1,2}(\-|\/|\.)\d{4}\1\d{1,2}$/
   }
   else // The year must be third 
   { 
      var reg1 = /^\d{1,2}(\-|\/|\.)\d{1,2}\1\d{2}$/
      var reg2 = /^\d{1,2}(\-|\/|\.)\d{1,2}\1\d{4}$/
   }
   
   // If it doesn't conform to the right format (with either a 2 digit year or 4 digit year), fail
   if ( (reg1.test(dateStr) == false) && (reg2.test(dateStr) == false) ) { return false; }
   var parts = dateStr.split(RegExp.$1); // Split into 3 parts based on what the divider was
   // Check to see if the 3 parts end up making a valid date
   if (format.substring(0, 1) == "M") { var mm = parts[0]; }
   else if (format.substring(1, 2) == "M") { var mm = parts[1]; } else { var mm = parts[2]; }
   if (format.substring(0, 1) == "D") { var dd = parts[0]; }
   else if (format.substring(1, 2) == "D") { var dd = parts[1]; } else { var dd = parts[2]; }
   if (format.substring(0, 1) == "Y") { var yy = parts[0]; }
   else if (format.substring(1, 2) == "Y") { var yy = parts[1]; } else { var yy = parts[2]; }
   if (parseFloat(yy) <= 50) { yy = (parseFloat(yy) + 2000).toString(); }
   if (parseFloat(yy) <= 99) { yy = (parseFloat(yy) + 1900).toString(); }
   var dt = new Date(parseFloat(yy), parseFloat(mm)-1, parseFloat(dd), 0, 0, 0, 0);
   if (parseFloat(dd) != dt.getDate()) { return false; }
   if (parseFloat(mm)-1 != dt.getMonth()) { return false; }
   return true;
}

/* This function makes sure that there are at least 3 characters in the name field and only valid characters and spaces  are entered in name field*/
function checkName(strng)
{
	var nameRE=/^[a-zA-Z_\s-&]+$/;
	if (strng.length < 3)  
	{
    alert( "Name should have at least 3 characters.\n");
		return false;
	 }
	 else if(!(strng.match(nameRE)))
	{
	   alert("Please enter valid name. Only valid chracters and spaces are allowed.");
		 return false;
	}
	else
	{
		return true;
	}
}
	
/* This fuction checks email address entered by user in standard format*/	
	
function checkEmail (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;
}

/* This funcion checks if phone number entered by user is either all numbers or formats like(XXX)xxx-xxxx*/

function checkPhone(strng){
 // var phoneRE=/^1?[\-]?\(?\d{3}\)?[\-]?\d{3}[\-]?\d{4}$/;
//	var phoneRE=/^(\(\d{3}\)|\d{3}) ?-?\d{3} ?-?\d{4}( ?(x|xtn|ext|extn|extension)?\.? ?\d{1,5})?$/i;
	 var phoneRE=/^(\(\d{3}\)|\d{3})?.? ?-?\d{3}?.? ?-?\d{4}( ?(x|xtn|ext|extn|extension)?\.? ?\d{1,5})?$/i;
	 if(!(strng.match(phoneRE)))
	 {
	   alert("Please enter valid 10 digit Phone number and extension if available.");
		 return false;
	}
	else
	{
		return true;
	}
}
/*\(?\s*\d{3}\s*[\)\.\-]?\s*\d{3}\s*[\-\.]?\s*\d{4}
/^(\+\d{1,3} ?)?(\(\d{1,5}\)|\d{1,5}) ?\d{3} ?\d{0,7}

                          ( ?(x|xtn|ext|extn|extension)?\.? ?\d{1,5})?$/i*/

/*This function validates all required fields and directs user back to respective field in case of error*/
function validateForm(thisform)
{
	with(thisform)
	{
	if(!(checkName(Name.value)))
	{ 
	  Name.focus();
		return false;
	}
	
	else if(!(checkEmail(Email.value.toLowerCase())))
	{ 
	  Email.focus();
	  return false;
	}
	
  else if(!(checkPhone(Phone.value)))
	{
	  Phone.focus();
		return false;
	}
	
  else if (!(isValidDate(prefDate.value, "MDY")))
	{
		alert("The preferred date is not in the correct format.");
		PrefDate.focus();
	  return false;
	}
	
	else if (!(isValidDate(altDate.value, "MDY")))
	{
		alert("The alternate date is not in the correct format.");
		AltDate.focus();
	  return false;
	}
		
  else
	{
		return true;
	}
}
}