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 trim(s)
{   var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not a whitespace, append to returnString.
    for (i = 0; i < s.length; i++)
    {   
        // Check that current character isn't whitespace.
        var c = s.charAt(i);
        if (c != " ") returnString += c;
    }
    return returnString;
}
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 checkPhone(strPhone){
	var bracket=3
	strPhone=trim(strPhone)
	if(strPhone.indexOf("+")>1) return false
	if(strPhone.indexOf("-")!=-1)bracket=bracket+1
	if(strPhone.indexOf("(")!=-1 && strPhone.indexOf("(")>bracket)return false
	var brchr=strPhone.indexOf("(")
	if(strPhone.indexOf("(")!=-1 && strPhone.charAt(brchr+2)!=")")return false
	if(strPhone.indexOf("(")==-1 && strPhone.indexOf(")")!=-1)return false
	s=stripCharsInBag(strPhone,validWorldPhoneChars);
	return (isInteger(s) && s.length >= minDigitsInIPhoneNumber);
}

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 E-mail ID")
		   return false
		}

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

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

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

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

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

 		 return true					
	}
	
function checkform ( form )
{
  if (form.realname.value == "") {
    alert( "Please enter your name." );
    form.realname.focus();
    return false ;
  }
  else if (form.telephone.value == "") {
  	alert("Please enter telephone number.");
	form.telephone.focus();
	return false;
  }
  else if (checkPhone(form.telephone.value) == false) {
  	alert("Invalide telephone number.");
	form.telephone.focus();
	return false;
  }
  else if (form.email.value == "") {
  	alert("Please enter your email address.");
	form.email.focus();
	return false;
  }
  else if (form.email2.value == "") {
  	alert("Please confirm your email address.");
	form.email2.focus();
	return false;
  }
  else if (form.email.value != form.email2.value) {
  	alert("E-mail addresses mismatch.");
	form.email2.focus();
	return false;
  }
  else if(echeck(form.email.value) == false) {
  	form.email.focus();
	return false;
  }
  return true ;
}