function emailCheck (emailStr) {

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

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]

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>4) {
   return false
}

if (len<2) {
   return false
}

return true;
}

function submitform() {

	if (!emailCheck(document.sub.email.value)) {
		alert("Please enter a valid Email Address.");
		document.sub.email.focus();
		return false;
	}
	else if (document.sub.fullname.value == "") {
		alert("Please enter your Name.");
		document.sub.fullname.focus();
		return false;
	}
	else {
		return true;
	}
}

function submitMBform() {

	if (!emailCheck(document.mbsub.mb-tyjty-tyjty.value)) {
		alert("Please enter a valid Email Address.");
		document.mbsub.mb-tyjty-tyjty.focus();
		return false;
	}
	else if (document.mbsub.mb-name.value == "") {
		alert("Please enter your Name.");
		document.mbsub.mb-name.focus();
		return false;
	}
	else {
		return true;
	}
}