Hi guys
I'm a newbie to javascript and have a real problem.

I'm using the checkbox calculator script http://javascript.internet.com/math-related/calculate.js

to use in a seminar registration form. It works fine in IE7, but in FF
nothing happens at all. When I look at the error console it gives the error:

Line 20: Calc is not defined

(line 20 is:

if (calc.item1.checked){
var witem1 = document.calc.item1.value = item1price;
} else {
var witem1 = document.calc.item1.value = 0;
}

I've looked all over the net to find out why FF
doesn't like this. Can anyone help? What should it be changed to?Many
thanks.

James

The script awaits a form named "calc" to be present.
Maybe you don't have it.

Now, some times ago, I've found myself in situations where the form.input notation didn't worked everywhere.
I don't remember if it's in ff or ie or another, but anyway.

A simple way to get through this is to use the dom getElementById(), after that you place an id on the form you want to checks:

function load(){
  window.status = "Made by Ville Leivo 15.07.2002"
}

function count(){
var item1price = 100;
var item2price = 100;
var item3price = 100;
var item4price = 100;
var calc=document.getElementById('myForm');
  
 // kortti
 if (calc.item1.checked){
   var witem1 = document.calc.item1.value = item1price;
 } else {
   var witem1 = document.calc.item1.value = 0;
 }

 if (calc.item2.checked){
   var witem2 = document.calc.item2.value = item2price;
 } else {
   var witem2 = document.calc.item2.value = 0;
 }

 // www-sivut
 if (calc.item3.checked) {
   var witem3 = document.calc.item3.value = item3price;
 } else {
   var witem3 = document.calc.item3.value = 0;
 }
 if (calc.item4.checked) {
   var witem4 = document.calc.item4.value = item4price;
 } else {
   var witem4 = document.calc.item4.value = 0;
 }
 calc.pay.value = witem1 + witem2 + witem3 + witem4;
}

This code look for a form with an id "myForm".
Try to modify your form, and use this js.

You're an absolute star! It worked first time, just by adding a form id as you suggested. I have two questions:

1. In your modified script, you have changed the last line from
document.calc.pay.value = witem1 + witem2 + witem3 + witem4;

to calc.pay.value = witem1 + witem2 + witem3 + witem4;

How come it works without this extra 'document' in front of calc? Why did you leave it off?

2. Why does this script need this id identifier? The script was a very popular download for over five years. What has changed in javascript language that means this is now required? I note that http://www.jibbering.com/faq/#FAQ4_41 has a reference to the getElementById(), although I haven't a clue what it's talking about.

Thanks again so much...it's great to have experts around to help newbies out!

Hehehe...
Thanks.

1:
look at the beginning of count()...
I picked the form via the getelementById.
No need to dig into the document to find it again...

2:
It don't need. Or to be more exact, it would not have needed it 3 years ago.
This script IS VERY OLD AND OUTDATED. 5 years means "elderly" in programming. It relies on the browser translating document.form_name.form_element notation to reaches them.
As I said to you in my first post, I've noticed some times ago that this method seems to be flawed in recent browser.
Maybe it's the fact that the browser being in a strict mode refuse to access the elements that way, or something else, but it don't work 100% of time on every browsers.

So, I simply defined the element to be reached via a DOM function, which is THE way to go in javascript today.
You should never have to do test and different logic between different browser, and DOM function are much more normalized that native browser functions.

Adding an ID to the form is simply the quickest and simplest way to go.
I could have given you a function that would have fetched every forms in your pages, and analyzed them to apply this validation, but it would have been a bit too much, I think.
As the function name says, getelementById() parse the document, and get a "link", or "reference" to the element having that precise id. Nothing more.
But remember that every id must be unique into the page, or else, only the last element rendered by the browser with that id will be taken in account.

If you are curious about DOM and javascript, take a look there:
http://developer.mozilla.org/en/docs...lement#Methods

But if you don't are used to programming, it will mostly looks gibberishes to you

Thanks again for this. So, just one more question.
What I have now is

<form name="calc" id="myForm" method="POST" action="">

This retains the 'calc' needed for the script, but places your id in it.
Could I have simply renamed the form 'myForm' then changed all occurrences of 'calc' in the script with myForm and achieved the same thing?

Merci!

No.
First, an id is different of an name and second, the method accessed to get the reference to the form are totally different.

The old scripts was trying to address the form via it's name.
Now you access the form via it's id.
Usually, the name and the id are set to the same value, but it's not mandatory, or only to be w3c strict compliant.

But, you could change the id to "calc", and modify the javascript to make a getElementById('calc') in place, and it would work the same. The two have just to stay in sync.

"de rien!"