// JavaScript Document
// 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 = 4;






function validateFeedback()
{
	var subject,comments,name,email,tel;
	subject = document.frmFeedback.subject.value;
	comments = document.frmFeedback.comments.value;
	name = document.frmFeedback.name.value;
	email = document.frmFeedback.email.value;
	tel = document.frmFeedback.tel.value;
	fax = document.frmFeedback.fax.value;
	
	
	if(subject == "" || subject == null)
	{
		alert("Subject field cannot be left empty.\n Please enter subject");
		document.frmFeedback.subject.focus();
		return false;
	}
	
	if(comments == null || comments == "")
	{
		alert("Comment field cannot be left empty.\n Please enter comment");
		document.frmFeedback.comments.focus();
		return false;
	}
	
	if(name == null || name == "")
	{
		alert("Name field cannot be left empty.\n Please enter Name");
		document.frmFeedback.name.focus();
		return false;
	}
	
	if(email.indexOf('@')=='-1'||email.indexOf('.')=='-1')
	{
		alert("Invalid email id.");	
		document.frmFeedback.email.focus();
		return false;
	}
	
	if(tel == "" || tel == null )
	{
		alert("Telephone field cannot be left empty.\n Please enter Telephone");
		document.frmFeedback.tel.focus();		
		return false;
	}
	else
	{
		if( ValidateForm() == false )
			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 checkInternationalPhone(strPhone)
{
	s=stripCharsInBag(strPhone,validWorldPhoneChars);
	return (isInteger(s) && s.length >= minDigitsInIPhoneNumber);
}

function ValidateForm()
{
	var tel =document.frmFeedback.tel.value;
	
	
	if ((tel==null)||(tel==""))
	{
		alert("Please Enter your Phone Number")
		document.frmFeedback.tel.focus()
		return false
	}
	if (checkInternationalPhone(tel)==false)
	{
		alert("Please Enter a Valid Phone Number")
		document.frmFeedback.tel.value=""
		document.frmFeedback.tel.focus()
		return false
	}
	

	return true
 }