function emailCheck (emailStr) {

var checkTLD=1;

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

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) {

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

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

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

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

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

for (var i=1;i<=4;i++) {
if (IPArray[i]>255) {
alert("The email destination IP address is invalid!");
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) {
alert("The email domain name does not seem to be valid.");
return false;
   }
}

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

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

return true;
}


function checkfrm(){
	if(document.form1.name.value==""){
		alert("Please tell us your name");
		document.form1.name.focus();
		return false;
	}
	if(document.form1.addr.value=="" || document.form1.tel.value=="" || document.form1.email.value==""){
		alert("Please tell us your postal address, telephone number or email address so that we can respond to your enquiry.");
		document.form1.addr.focus();
		return false;
	}
	if(document.form1.addr.value==document.form1.name.value || document.form1.tel.value==document.form1.email.value){
		alert("Please check the details you have entered as there seems to be some unexpected similarity between you name and your address or your phone number and your email address!");
		document.form1.addr.focus();
		return false;
	}
	if(document.form1.txt.value==""){
		alert("You have not written any message for us to read!");
		document.form1.txt.focus();
		return false;
	}
	if (document.form1.email.value != "")
	{
	return emailCheck(document.form1.email.value);
	document.form1.email.focus();
	}

}