/**
 * DHTML email validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)
 */

function IsValidEmail(InputID)
{
	var Input = document.getElementById(InputID);
	var str = Input.value;
	
	if ((str==null)||(str==""))
	{
		return false
	}	
	
	var at="@"
	var dot="."
	var lat=str.indexOf(at)
	var lstr=str.length
	var ldot=str.indexOf(dot)
	
	if (str.indexOf(at)==-1)
	{
		return false
	}

	if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr)
	{
		return false
	}

	if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr)
	{
		return false
	}

	if (str.indexOf(at,(lat+1))!=-1)
	{
		return false
	}

	if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot)
	{
		return false
	}

	if (str.indexOf(dot,(lat+2))==-1)
	{
		return false
	}
		
	if (str.indexOf(" ")!=-1)
	{
		return false
	}

 	return true					
}


/**
 * DHTML phone number validation script. Courtesy of SmartWebby.com (http://www.smartwebby.com/dhtml/)
 */

// Declaring required variables
var digits = "0123456789";
// non-digit characters which are allowed in phone numbers
var phoneNumberDelimiters = "()- ";
// characters which are allowed in international phone numbers
// (a leading + is OK)
var validWorldPhoneChars = phoneNumberDelimiters + "+";
// Minimum no of digits in an international phone no.
var minDigitsInIPhoneNumber = 10;

function IsValidPhoneNo(InputID)
{
	var Input = document.getElementById(InputID);
	var str = Input.value;
	
	if ((str==null)||(str==""))
	{
		return false
	}
	
	s=stripCharsInBag(str,validWorldPhoneChars);
	
	if (s.length <= 11)
	{
		return (isInteger(s) && s.length >= minDigitsInIPhoneNumber);
	}
	else
	{
		return false;	
	}
}


<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->
<!-- Original code by Peter Haydon -->
<!-- peter_haydon@lineone.net -->

function IsValidPostcode(InputID)
{
	var Input = document.getElementById(InputID);
	var str = Input.value;
	var size = str.length;
	str = str.toUpperCase(); //Change to uppercase
	
	
	while (str.slice(0,1) == " ") //Strip leading spaces
	{
		str = str.substr(1,size-1);size = str.length
	}
	
	while(str.slice(size-1,size)== " ") //Strip trailing spaces
	{
		str = str.substr(0,size-1);size = str.length
	}
	
	if (size < 6 || size > 8)
	{ //Code length rule
		return false;
	}
	
	if (!(isNaN(str.charAt(0))))
	{ //leftmost character must be alpha character rule
		return false;
	}
	
	if (isNaN(str.charAt(size-3)))
	{ //first character of inward code must be numeric rule
		return false;
	}
	
	if (!(isNaN(str.charAt(size-2))))
	{ //second character of inward code must be alpha rule
		return false;
	}
	
	if (!(isNaN(str.charAt(size-1))))
	{ //third character of inward code must be alpha rule
	   return false;
	}
	
	count1 = str.indexOf(" ");
	count2 = str.lastIndexOf(" ");
	if (count1 != count2)
	{//only one space rule
		return false;
	}
	

	return true;
}




 
function isInteger(s)
{   var i;
    for (i = 0; i < s.length; i++)
    {   
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag)
{   var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function ForceTextboxStyle(IdArray)
{
	var i;
	var Input;
	
	for (i = 0; i < IdArray.length; i++)
	{
		Input = document.getElementById(IdArray[i]);	
		Input.style.backgroundColor = "#ffffff";
		Input.style.border = "1px solid #7f9db9";
	}
}