//Check form values
function check_form(form)
{
	var firstname = form.firstname.value;
	var lastname = form.lastname.value;
	var email = form.email.value;

	if (!checkName(firstname)) {
		alert("That name is not valid.\r\nPlease write a valid name");
	    return false;
	} else if (!checkName(lastname)) {
		alert("That last name is not valid.\r\nPlease write a valid last name");
	    return false;
	}
	else if (!isEmail(email)) {
		alert("Please provide a valid email");
		return false;
	}
	else {
		//Submit Form
		return true;
	}
}

function checkName(name) {
	if (name.length<2) {
    	return false;
	} else if (!isAlphabetic(name)) {
    	return false;
	} else {
    	return true;
	}
}

function isAlphabetic(s){
  var i;
  for (i=0;i<s.length;i++) {
    var c=s.charAt(i);
    if (!isLetter(c))
        return false;
  }
  // All are letters
  return true;
}

function isLetter(c) {
  return ( ((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")) || (c==" ") || (c=="'") || (c=="-") );
}

function checkNum(num) {
  if (num.length<2)
    return false;
  else if (!isNumber(num))
    return false;
  else
    return true;
}

function isNumber(s) {
  var i;
  for (i=0;i<s.length;i++) {
	var c=s.charAt(i);
    if (!isDigit(c))
	  return false;
  }
  // All are digits
  return true;
}

function isDigit(c) {
  return ( ((c >= "0") && (c <= "9")) || (c=="-") || (c=="(") || (c==")") || (c=="[") || (c=="]") || (c==" ") );
}

function isEmpty(s) {
  return ((s == null) || (s.length == 0));
}

function isEmail(s) {
	var email = trim(s);
    var emailReg = "^[\\w-_\.]*[\\w-_\.]\@[\\w]\.+[\\w]+[\\w]$";
    var regex = new RegExp(emailReg);
    return regex.test(email);
}

function trim(str)
{
   return str.replace(/^\s*|\s*$/g,"");
}