var numb = '0123456789';
var lwr = 'abcdefghijklmnopqrstuvwxyz';
var upr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';

/*Validate Email Address*/
function emailCheck (emailStr) {

var checkTLD=0;

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

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=emailStr.match(emailPat);

if (matchArray==null) {
return false;
}
var user=matchArray[1];
var domain=matchArray[2];

for (i=0; i<user.length; i++) {
if (user.charCodeAt(i)>127) {
return false;
   }
}
for (i=0; i<domain.length; i++) {
if (domain.charCodeAt(i)>127) {
return false;
   }
}

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

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

// this is an IP address

for (var i=1;i<=4;i++) {
if (IPArray[i]>255) {
return false;
   }
}
return true;
}

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) {
return false;
   }
}

if (checkTLD && domArr[domArr.length-1].length!=2 && 
domArr[domArr.length-1].search(knownDomsPat)==-1) {
return false;
}

if (len<2) {
return false;
}

return true;
}

/*Validate Alphabetic,Alphanumeric,numeeric,lower,upper*/
function isValid(parm,val) {
if (parm == "") return true;
for (i=0; i<parm.length; i++) {
if (val.indexOf(parm.charAt(i),0) == -1) return false;
}
return true;
}
function isNum(parm) {return isValid(parm,numb);}
function isLower(parm) {return isValid(parm,lwr);}
function isUpper(parm) {return isValid(parm,upr);}
function isAlpha(parm) {return isValid(parm,lwr+upr);}
function isAlphanum(parm) {return isValid(parm,lwr+upr+numb);}

/*Validate Form*/
function validate_form(){
if(document.frmFeedback.firstname.value.length<=0 || !isAlpha(document.frmFeedback.firstname.value))
{
alert('Enter a valid First name');
document.frmFeedback.firstname.focus();
}
else if(document.frmFeedback.fromemail.value.length<=0 || !emailCheck(document.frmFeedback.fromemail.value))
{
alert('Enter a valid email Id');
document.frmFeedback.fromemail.focus();
}
else if(document.frmFeedback.phone.value.length<=0 || !checkInternationalPhone(document.frmFeedback.phone.value))
{
alert('Enter a valid phone number [Note: International Format supported]');
document.frmFeedback.phone.focus();
}
else if(document.frmFeedback.fax.value.length<=0 || !checkInternationalPhone(document.frmFeedback.phone.value))
{
alert('Enter a valid fax number [Note: International Format supported]');
document.frmFeedback.fax.focus();
}
else if(document.frmFeedback.message.value.length<=0)
{
alert('Enter a valid Comment');
document.frmFeedback.message.focus();
}
else
{
document.frmFeedback.submit();
}
}