function isValidEmail (entered, alertbox) {
	
	with (entered){
		/* The following variable tells the rest of the function whether or not	to verify that the address ends in a two-letter country or well-known
		TLD.  1 means check it, 0 means don't. */
		
		var checkTLD=1;
		
		/* The following is the list of known TLDs that an e-mail address must end with. */
		var knownDomsPat=/^(com|net|org|edu|int|mil|gov|arpa|biz|aero|name|coop|info|pro|museum)$/;
		
		/* The following pattern is used to check if the entered e-mail address
		fits the user@domain format.  It also is used to separate the username
		from the domain. */
		
		var emailPat=/^(.+)@(.+)$/;
		
		/* The following string represents the pattern for matching all special
		characters.  We don't want to allow special characters in the address. 
		These characters include ( ) < > @ , ; : \ " . [ ] */
		
		var specialChars="\\(\\)><@,;:\\\\\\\"\\.\\[\\]";
		
		/* The following string represents the range of characters allowed in a 
		username or domainname.  It really states which chars aren't allowed.*/
		
		var validChars="\[^\\s" + specialChars + "\]";
		
		/* The following pattern applies if the "user" is a quoted string (in
		which case, there are no rules about which characters are allowed
		and which aren't; anything goes).  E.g. "jiminy cricket"@disney.com
		is a legal e-mail address. */
		
		var quotedUser="(\"[^\"]*\")";
		
		/* The following pattern applies for domains that are IP addresses,
		rather than symbolic names.  E.g. joe@[123.124.233.4] is a legal
		e-mail address. NOTE: The square brackets are required. */
		
		var ipDomainPat=/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/;
		
		/* The following string represents an atom (basically a series of non-special characters.) */
		
		var atom=validChars + '+';
		
		/* The following string represents one word in the typical username.
		For example, in john.doe@somewhere.com, john and doe are words.
		Basically, a word is either an atom or quoted string. */
		
		var word="(" + atom + "|" + quotedUser + ")";
		
		// The following pattern describes the structure of the user
		
		var userPat=new RegExp("^" + word + "(\\." + word + ")*$");
		
		/* The following pattern describes the structure of a normal symbolic
		domain, as opposed to ipDomainPat, shown above. */
		
		var domainPat=new RegExp("^" + atom + "(\\." + atom +")*$");
		
		/* Finally, let's start trying to figure out if the supplied address is valid. */
		
		/* Begin with the coarse pattern to simply break up user@domain into
		different pieces that are easy to analyze. */
		
		var matchArray=value.match(emailPat);
		
		if (matchArray==null) {
		
		/* Too many/few @'s or something; basically, this address doesn't
		even fit the general mould of a valid e-mail address. */
		
		if (alertbox) {alert("Email address seems incorrect (check @ and .'s)")};
		return false;
		}
		var user=matchArray[1];
		var domain=matchArray[2];
		
		// Start by checking that only basic ASCII characters are in the strings (0-127).
		
		for (i=0; i<user.length; i++) {
		if (user.charCodeAt(i)>127) {
		if (alertbox) {alert("Ths username contains invalid characters.")};
		return false;
		   }
		}
		for (i=0; i<domain.length; i++) {
		if (domain.charCodeAt(i)>127) {
		if (alertbox) {alert("Ths domain name contains invalid characters.")};
		return false;
		   }
		}
		
		// See if "user" is valid 
		
		if (user.match(userPat)==null) {
		
		// user is not valid
		
		if (alertbox) {alert("The username doesn't seem to be valid.")};
		return false;
		}
		
		/* if the e-mail address is at an IP address (as opposed to a symbolic
		host name) make sure the IP address is valid. */
		
		var IPArray=domain.match(ipDomainPat);
		if (IPArray!=null) {
		
		// this is an IP address
		
		for (var i=1;i<=4;i++) {
		if (IPArray[i]>255) {
		if (alertbox) {alert("Destination IP address is invalid!")};
		return false;
		   }
		}
		return true;
		}
		
		// Domain is symbolic name.  Check if it's valid.
		 
		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) {
		if (alertbox) {alert("The domain name does not seem to be valid.")};
		return false;
		   }
		}
		
		/* domain name seems valid, but now make sure that it ends in a
		known top-level domain (like com, edu, gov) or a two-letter word,
		representing country (uk, nl), and that there's a hostname preceding 
		the domain or country. */
		
		if (checkTLD && domArr[domArr.length-1].length!=2 && 
		domArr[domArr.length-1].search(knownDomsPat)==-1) {
		if (alertbox) {alert("The address must end in a well-known domain or two letter " + "country.")};
		return false;
		}
		
		// Make sure there's a host name preceding the domain.
		
		if (len<2) {
		if (alertbox) {alert("This address is missing a hostname!")};
		return false;
		}
		
		// If we've gotten this far, everything's valid!
		return true;
	}
}

function inRange(entered, min, max, alertbox, datatype){
// checks a value is in the max and min range specified
with (entered)
	{
	checkvalue=parseFloat(value);
	if (datatype)
	{smalldatatype=datatype.toLowerCase();
	if (smalldatatype.charAt(0)=="i") {checkvalue=parseInt(value)};
	}
	if ((parseFloat(min)==min && checkvalue<min) || (parseFloat(max)==max && checkvalue>max) || value!=checkvalue)
		{if (alertbox!="") {alert(alertbox);} return false;}
	else {return true;}
	}
}

function isEmpty(entered, alertbox){
// checks a value is specified (not empty)
with (entered)
	{
	if (value==null || value=="")
		{if (alertbox!="") {alert(alertbox);} return false;}
	else {return true;}
	}
}

function isInteger(entered, alertbox){
// checks for an integer (+ or -)
with (entered)
	{
	if (value!=parseInt(value))
		{if (alertbox!="") {alert(alertbox);} return false;}
	else {return true;}
	}
}

function isFloat(entered, alertbox){
// checks for a decimal 
with (entered)
	{
	if (value!=parseFloat(value))
		{if (alertbox!="") {alert(alertbox);} return false;}
	else {return true;}
	}
}


function isSelected(entered, alertbox, thistype){
// checks for a selected item (mandatory check)
with (entered)
	{
	if (thistype.toLowerCase()=='select')
		{
		if (selectedIndex==-1 || options[selectedIndex].value=="")
			{if (alertbox!="") {alert(alertbox);} return false;}
		else {return true;}
		}
	if (thistype.toLowerCase()=='multiselect')
		{
		if (selectedIndex==-1)
			{if (alertbox!="") {alert(alertbox);} return false;}
		else {return true;}
		}	
	if (thistype.toLowerCase()=='radio' || thistype.toLowerCase()=='checkbox')
		{
		var count=0;
		for (var i=0;i<entered.length;i++)
			{if (entered[i].checked==true){count++;}}
		if (count==0)
			{if (alertbox!="") {alert(alertbox);} return false;}
		else {return true;}
		}
	}
}

function deletekey(e) {
    var thekeycode;

    if (document.all) {
        e = window.event;
		var thekeycode = e.keyCode;
    	}
    else
        if (document.layers)
		var thekeycode = e.which;
 	
	// 46 Delete, 8 Backspace
    if (thekeycode  == 46 || thekeycode == 8) {
        if (document.layers){
            return true;}
        else if (document.all){
            //e.returnValue = true;
			return true;}
    	}
	
}

function MaxChars(entered,maxChars,label)
// checks a field has not exceeded max characters
{
with (entered)
	{
	var charsover=value.length-maxChars;
	if (charsover >= 0)
	//if (value.length > maxChars)
		{
		if (label== null){label=entered.name;}
		var charsoverstring=''
		if (charsover!=0)
			charsoverstring=' (currently ' + charsover + ' character(s) too many)';
		alert('The ' + label + ' can have a maximum of ' + maxChars + ' characters.' + charsoverstring);return true;
		}
	else 
		{return false;}
	}
}

function MinChars(entered,minChars,label)
// checks a field has not exceeded max characters
{
with (entered)
	{
	var charsunder=minChars-value.length;
	if (charsunder > 0)
	//if (value.length > maxChars)
		{
		if (label== null){label=entered.name;}
		var charsunderstring=''
		if (charsunder>0)
			charsunderstring=' (currently ' + charsunder + ' character(s) too few)';
		alert('The ' + label + ' can have a minimum of ' + minChars + ' characters.' + charsunderstring);return true;
		}
	else 
		{return false;}
	}
}

/*
function validateform(thisform)
{
// This function checks the entire form before it is submitted
// Note: This function needs to be customized to fit your form

with (thisform)
{
if (emailvalidation(Email,"Illegal E-mail")==false) {Email.focus(); return false;};
if (valuevalidation(Value,0,5,"Value MUST be in the range 0-5")==false) {Value.focus(); return false;};
if (digitvalidation(Digits,3,4,"You MUST enter 3 or 4 integer digits","I")==false) {Digits.focus(); return false;};
if (emptyvalidation(Whatever,"The textfield is empty")==false) {Whatever.focus(); return false;};
}
}*/