var digits = "0123456789";

var phoneNumberDelimiters = "()- ";

var validWorldPhoneChars = phoneNumberDelimiters + "+";

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.frmdemo.custom_phone_

	if ((Phone.value==null)||(Phone.value=="")){

		alert("Please Enter your Phone Number")

		Phone.focus()

		return false

	}

	if (checkInternationalPhone(Phone.value)==false){

		alert("Please Enter a Valid Phone Number")

		Phone.value=""

		Phone.focus()

		return false

	}

	return true

 }