// 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);
}

function ValidateForm(){
	var Phone=document.formcheck.Telephone
	
	if ((Phone.value==null)||(Phone.value=="")){
		alert("IMPORTANT:\nThe Call Prevention Registry require a valid\nphone number so we can process your request\n\nPlease enter your Phone Number")
		Phone.focus()
		return false
	}
	if (checkInternationalPhone(Phone.value)==false){
		alert("IMPORTANT:\nThe Call Prevention Registry require a valid\nphone number so we can process your request\n\nPlease take note of the following restrictions:\n-----------------------------------------------------------------------------------\n1. Characters like these are not permitted: . , / * @ # + ( )\n2. Alpha characters are NOT permitted\n3. Please include your full STD code\n4. DO NOT include international dialling codes\n5. A valid phone number requires at least 10 digits\n6. Do not leave space in between digits, eg 01234567890\n-----------------------------------------------------------------------------------\n\n>> Please enter a valid Phone Number")
		Phone.value=""
		Phone.focus()
		return false
	}
	return true
 }