// JavaScript Document
// <input name="postcode" onblur="new PostCodeValidator(this).validate()" type="text" value="<?php echo $fields['postcode'] ?>" />
// call using similar to above example

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// Kill return allowing form submission. IE Only. If more than one textbox, return will not submit.
function noenter() {
  return !(window.event && window.event.keyCode == 13); }
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// extends class attributes and values from supplied parent class
// use: this.extendsClass(new ParentClass());
Object.prototype.extendsClass = function(){ 
		 for (sProperty in arguments[0]) { 
						 this[sProperty] = arguments[0][sProperty]; 
		 } 
}
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// form field validators
// parent class handles color changes and validation
function Validator(){
	this.hilite = function (){
		this.elm.style.borderColor='#ff0000';
		this.elm.style.borderWidth=2;
		this.elm.style.borderStyle='solid';
		this.elm.focus();
	}
	this.revert = function (){
		this.elm.style.borderColor='';
		this.elm.style.borderWidth='';
		this.elm.style.borderStyle='';
	}
	this.validate = function (){
		if(!this.isValid()) {
			alert(this.errorMsg);
			this.hilite();
		} else {
			this.revert();
		}
	}
}
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// Y2k check function
function y2k(number) {
	return (number < 1000) ? number + 1900 : number;
	}
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// child of Validator class
// param elm - form element object
// method isValid - defines validation routine
function DateValidator(elm){
	this.extendsClass(new Validator());
	this.errorMsg = 'All dates must be in dd-mm-yyyy format\nbetween 01-01-1900 / 31-12-2099';
	this.elm = elm;
	this.isValid = function (){
		if(this.elm.value!=''){
			var objRegExp = new RegExp("^(0[1-9]|[12][0-9]|3[01])-(0[1-9]|1[012])-(19|20)[0-9]{2}$");
			if(!objRegExp.test(this.elm.value)){
				return false;
			} else {
				var date  = this.elm.value.substring(0,2);
				var month = this.elm.value.substring(3,5);
				var year  = this.elm.value.substring(6,10);
				//--
				var test = new Date(year,month-1,date);
				// checks for valid date (traps February leap years too)
				if (year == y2k(test.getYear()) && (month-1 == test.getMonth()) && (date == test.getDate())) {
					return true;
				} else {
					return false;
				}
			}
		} else {
			return true;
		}
	}
}
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function PostCodeValidator(elm){
	this.extendsClass(new Validator());
	this.errorMsg = 'Postcode is in incorrect format.\n';
	this.elm = elm;
	this.isValid = function (){
		if(this.elm.value!=''){
			var objRegExp = new RegExp("^[A-Za-z]{1,2}[0-9A-Za-z]{1,3}[ ]?([0-9]{0,1}[A-Za-z]{2})?$");
			if(!objRegExp.test(this.elm.value)){
				return false;
			} else {
				return true;
			}
		} else {
			return true;
		}
	}
}
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function EmailAddressValidator(elm){
	this.extendsClass(new Validator());
	this.elm = elm;
	this.isValid = function (){
		if(this.elm.value!=''){
		//---
		/* 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=this.elm.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. */
		
		this.errorMsg = ("Email address is 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) {
				this.errorMsg = ("This username contains invalid characters.");
				return false;
		   }
		}
		for (i=0; i<domain.length; i++) {
			if (domain.charCodeAt(i)>127) {
				this.errorMsg = ("This domain name contains invalid characters.");
				return false;
		   }
		}
		
		// See if "user" is valid 
		
		if (user.match(userPat)==null) {
		
		// user is not valid
		
		this.errorMsg = ("Username is not 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) {
		this.errorMsg = ("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) {
		this.errorMsg = ("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) {
		this.errorMsg = ("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) {
		this.errorMsg = ("This address is missing a hostname!");
		return false;
		}
		
		// If we've gotten this far, everything's valid!
		return true;
		//---
		} else {
			return true;
		}
	}
}
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