//
// If the string matches the regular expression it is all letters
//
function isAlphabet(fString)
{
	var alphaExp = /^([a-zA-Z]+)$/;
	
	if(fString.match(alphaExp))
	{
		return true;
	}
	else
	{
		return false;
	}
}

//
// Check the email string entered
//
function echeck(str)
{
    var at      = "@";
    var dot     = ".";
	var lat     = str.indexOf(at)
	var lstr    = str.length
	var ldot    = str.indexOf(dot)
		
    if (str.indexOf(at) == -1)
    {
        alert("Invalid Email Address")
        return false
    }

	if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr)
	{
	   alert("Invalid Email Address")
	   return false
	}

	if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr)
	{
        alert("Invalid Email Address")
	    return false
	}

	 if (str.indexOf(at,(lat+1))!=-1)
	 {
        alert("Invalid Email Address")
	    return false
	 }

	 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot)
	 {
        alert("Invalid Email Address")
	    return false
	 }

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

	 return true					
}

// 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 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 checkInternationalPhone(strPhone)
{
    s = stripCharsInBag(strPhone,validWorldPhoneChars);
    return (isInteger(s) && s.length >= minDigitsInIPhoneNumber);
}