function emailCheck (emailStr1)
{
		var emailStr = emailStr1.value;
	
		var checkTLD=1;
		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) 
		{
				alert("Email address seems incorrect (check @ and .'s)");
				emailStr1.value='';
				emailStr1.focus();
				return false;
		}
		var user=matchArray[1];
		var domain=matchArray[2];
		
		for (i=0; i<user.length; i++) 
		{
				if (user.charCodeAt(i)>127) 
				{
						alert("Ths username contains invalid characters.");
						emailStr1.value='';
						emailStr1.focus();
						return false;
				}
		}
		for (i=0; i<domain.length; i++) 
		{
				if (domain.charCodeAt(i)>127) 
				{
						alert("Ths domain name contains invalid characters.");
						emailStr1.value='';
						emailStr1.focus();
						return false;
				}
		}
		
		if (user.match(userPat)==null) 
		{
				alert("The username doesn't seem to be valid.");
				emailStr1.value='';
				emailStr1.focus();
				return false;
		}
		
		var IPArray=domain.match(ipDomainPat);
		if (IPArray!=null) 
		{
				for (var i=1;i<=4;i++) 
				{
						if (IPArray[i]>255) 
						{
								alert("Destination IP address is invalid!");
								emailStr1.value='';
								emailStr1.focus();
								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 domain name does not seem to be valid.");
						emailStr1.value='';
						emailStr1.focus();
						return false;						
				}
		}
		
		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.");
				emailStr1.value='';
				emailStr1.focus();
				return false;				
		}
		
		if (len<2) 
		{
				alert("This address is missing a hostname!");
				emailStr1.value='';
				emailStr1.focus();
				return false;
		}		
		return true;
}