// JavaScript Document

function trim(str) {
	return str.replace(/^\s+|\s+$/g, '');
}

function emailCheck (emailStr) {

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 +")*$");


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("Incorrect Email address");
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 validation() {
	if(trim(document.getElementById("name").value) == ""){
		alert("Please enter your Name");
		return false;
	}

	if(!emailCheck (document.getElementById("email").value)){
		return false;
	}

	if(document.getElementById("subject").selectedIndex == 0){
		alert("Please select your subject.");
		return false;
	}

	if(trim(document.getElementById("comments").value) == ""){
		alert("Please enter your comments");
		return false;
	}

	return true;
}