function myGetElementById(e) {
	if(typeof(e)!='string') return e;
	if(document.getElementById) e=document.getElementById(e);
	else if(document.all) e=document.all[e];
	else e=null;
	return e;
	}

function checkPrompt (field, String) {
	alert (String);
	field.focus();
	return;
}

// http://javascript.internet.com/forms/email-address-validation.html
function checkEmail (emailStr) {
	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) {
		return("Email address seems incorrect (check @ and .'s)");
	}
	var user=matchArray[1];
	var domain=matchArray[2];

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

	if (user.match(userPat)==null) {
		return("The username doesn't seem to be valid.");
	}

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

		for (var i=1;i<=4;i++) {
			if (IPArray[i]>255) {
				return("Destination IP address is invalid!");
			}
		}
		return "";
	}

	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("The domain name does not seem to be valid.");
		}
	}

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

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

	return "";
}

// http://javascript.internet.com/forms/val-zip-code.html
function checkZIP (zipStr) {
	var valid = "0123456789-";
	var hyphencount = 0;
	if(!zipStr) { zipStr = "12345"; }

	if (zipStr.length!=5 && zipStr.length!=10) {
		return("Please enter your 5 digit or 5 digit+4 zip code.");
	}
	for (var i=0; i < zipStr.length; i++) {
		var temp = "" + zipStr.substring(i, i+1);
		if (temp == "-") hyphencount++;
		if (valid.indexOf(temp) == "-1") {
			return("Invalid characters in your zip code.");
		}
		if ((hyphencount > 1) || ((zipStr.length==10) && ""+zipStr.charAt(5)!="-")) {
			return("The hyphen character should be used with a properly formatted 5 digit+four zip code, like '12345-6789'.");
		}
	}
	return "";
}

function checkPersonalDetails (form) {
	var firstname = myGetElementById('firstname');
	var lastname = myGetElementById('lastname');
	var title = myGetElementById('title');
	if(!title) { title = "Professor"; }
	var company = myGetElementById('company');
	if(!company) { company = "ACME"; }
	var email = myGetElementById('email');
	var phone = myGetElementById('phone');
	if(!phone) { phone = "000-000-000"; }
	var address1 = myGetElementById('address1');
	if(!address1) { address1 = "Street 123"; }
	var city = myGetElementById('city');
	if(!city) { city = "Town"; }
	var state = myGetElementById('state');
	if(!state) { state = "state"; }
	var zip = myGetElementById('zip');
	if(!zip) { zip = "12345"; }
	var country = myGetElementById('country');
	if(!country) { country = "USA"; }
	
	if (firstname.value == "") {
		checkPrompt (firstname, "Please enter your first name.");
		return (false);
	}
	if (lastname.value == "") {
		checkPrompt (lastname, "Please enter your last name.");
		return (false);
	}
	if (title.title == "") {
		checkPrompt (title, "Please enter your title.");
		return (false);
	}
	if (company.value == "") {
		checkPrompt (company, "Please enter your company.");
		return (false);
	}
	var emailAlert = checkEmail(email.value);
	if (emailAlert != "") {
		checkPrompt (email, emailAlert);
		return (false);
	}
	if (phone.value == "") {
		checkPrompt (phone, "Please enter a phone number at which\nyou may be reached in case of problems\nwith this submission.");
		return (false);
	}
	if (address1.value == "") {
		checkPrompt (address1, "Please enter your mailing address.");
		return (false);
	}
	if (city.value == "") {
		checkPrompt (city, "Please enter your city.");
		return (false);
	}
	if (state.value == "") {
		checkPrompt (state, "Please enter your state.");
		return (false);
	}
	var zipAlert = checkZIP(zip.value);
	if (zipAlert != "") {
		checkPrompt (zip, zipAlert);
		return (false);
	}
	if (country.value == "") {
		checkPrompt (country, "Please enter your country.");
		return (false);
	} else
		return (true);
}