function validateEmail(emailStr) {
	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("Please enter a valid Email address (check @ and .'s)");
		return false;
	}
	
	var user=matchArray[1];
	var domain=matchArray[2];
	
	if (user.match(userPat)==null) {
    	alert("The 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("Destination IP address is invalid!");
				return false;
			}
		}
		return true;
	}
	
	var domainArray=domain.match(domainPat);
	if (domainArray==null) {
		alert("The domain name doesn't seem to be valid.");
		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>3) {
		alert("The address must end in a three-letter domain, or two letter country.");
		return false;
	}
	
	if (len<2) {
		var errStr="This address is missing a hostname!";
		alert(errStr);
		return false;
	}
	return true;
}

function validateNumeric(field) 
  {
  var valid = "0123456789";
  var ok = "yes";
  var temp;
  for (var i=0; i<field.value.length; i++) 
    {
    temp = "" + field.value.substring(i, i+1);
    if (valid.indexOf(temp) == "-1") ok = "no";
    }
  if (ok == "no" || field.value == "") 
    {
    field.value = "";
    field.focus();
    field.select();
    return false;
    }
  return true;
  }

function trim(str) {
   return str.replace(/^\s*|\s*$/g,"");
}
  
function isPositive(n) {
	if (isNaN(n) || n <= 0) {
		return(false);
	} else {
		return(true);
	}
}

function validText(el, s) {
	if (trim(el.value) == "") {
		alert("Please enter your " +s +".");
		el.focus();
		return false;
	}
	return true;
}