var maxFriends = 20;

function email_check(str) {
  var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
  return (filter.test(str));
}

function ValidateSweepstakesForm(){
	var fName=document.frmSweepstakes.sweep_name
	var fEmail=document.frmSweepstakes.sweep_email

	if ((fName.value==null)||(fName.value=="")){
		alert("Please enter your name")
		fName.focus()
		return false
	}	
	if ((fEmail.value==null)||(fEmail.value=="")){
		alert("Please enter your e-mail address")
		fEmail.focus()
		return false
	}
	if (email_check(fEmail.value)==false){
		alert("Please enter a valid e-mail address")
		fEmail.focus()
		return false
	}
	return true
 }

function ValidateTellYourFriendsForm(){
	var fName=document.frmTellYourFriends.tyf_name
	var fEmail=document.frmTellYourFriends.tyf_email
	
	if ((fName.value==null)||(fName.value=="")){
		alert("Please enter your name")
		fName.focus()
		return false
	}	
	if ((fEmail.value==null)||(fEmail.value=="")){
		alert("Please enter your e-mail address")
		fEmail.focus()
		return false
	}
	if (email_check(fEmail.value)==false){
		alert("Please enter a valid e-mail address")
		fEmail.focus()
		return false
	}

    fEmail=document.getElementById("friend_email1");
	if ((fEmail.value==null)||(fEmail.value=="")){
		alert("Please enter at least one friend's email address")
		fEmail.focus()
		return false
	}

	for (i=1;i<=maxFriends;i++) {
	  fEmail=document.getElementById("friend_email"+i);
	  if ((!((fEmail.value==null)||(fEmail.value=="")))&&(email_check(fEmail.value)==false)) {
		alert("Please enter valid e-mail addresses for your friends")
		fEmail.focus()
		return false
	  }
    }
	return true
 }

function getVisibleFriends() {
  var visibleFriends = maxFriends;;
  var this_row;
  var found = false;
  var i=1;
  while ((i<=maxFriends)&&(!found)) {
	  this_row = document.getElementById("friends_row"+i)
	  if (this_row.style.display == 'none') {
		  visibleFriends = i-1;
		  found = true;
	  }
	  i++;
  }
  return visibleFriends;
}

function MoreFriends() {
  var friendsCount = getVisibleFriends();
  if (friendsCount<maxFriends) {
    friendsCount++;
	var this_row = document.getElementById("friends_row"+friendsCount);
	this_row.style.display = 'block';
  }
  showMoreLessButtons(friendsCount);
}

function LessFriends() {
  var friendsCount = getVisibleFriends();
  if (friendsCount>1) {
	var this_row = document.getElementById("friends_row"+friendsCount);
	this_row.style.display = 'none';
	friendsCount--;
  }
  showMoreLessButtons(friendsCount);
}

function showMoreLessButtons(friendsCount) {
  if (friendsCount<maxFriends) {
    document.getElementById("btnMore").style.visibility = 'visible';
  } else {
    document.getElementById("btnMore").style.visibility = 'hidden';
  }
  if (friendsCount>1) {
    document.getElementById("btnLess").style.visibility = 'visible';
  } else {
    document.getElementById("btnLess").style.visibility = 'hidden';
  }
  var fFriendName=document.getElementById("friend_name"+friendsCount);
  fFriendName.focus();
}