I've bookmarked the link, so I'll see if I can get round to it - in the meantime I'm just happy that I've got it working, even if it's not the cleanest way of doing it.

I second Peter's recommendation to use jQuery. As well as simplifying a lot of the DOM-related stuff you'll need to do, it also abstracts the various browser incompatabilities, saving you a lot of headaches.

Another thing, too: DOM-related functions are pretty slow, so stuff like this:

for (var i=0; i < document.listofoptions.Grp1.length; i++)
   {
   if (document.listofoptions.Grp1[i].checked)
      {
      var rad_val = document.listofoptions.Grp1[i].value;
      }
   }
 

Could be better written like this:

var radGrp = document.listofoptions.Grp1,
    i = 0, len = radGrp.length,
    radVal;
 
while (!radVal && i < len) {
    if (radGrp[i].checked) {
        radVal = radGrp[i].value;
    }
    i += 1;
}

This way you're cacheing the DOM element names, so they don't need to be looked up for each loop iteration, and also the conditions of the loop mean you don't continue to loop once you've found the value you want. It also saves you some typing if you need to do more stuff with the elements within the loop :)

The way you've done it is fine for such a small-scale project, but it's a good idea to get into the habit of doing things "properly" from the start. If you really want to learn JavaScript the right way, I'd seriously recommend this book by Douglas Crockford.

JavaScript: The Good Parts? Must be a pretty short book.

So it is! :$

Just checking cos you've not explicitly said so: you're not calculating a price client-side and the trusting it server-side are you?

Eh? JavaScript is a fine language, it just has stupid bits that should be avoided. What don't you like about it?

It's a fine language which has been (historically) pisspoorly and inconsistently implemented/supported is the problem I think.

I mean, before jquery pretty much anything but the most simple of JS scripts had to start off with a huge block of conditional stuff to check which browser was being used and do stuff differently, depending. (And that's still there, just jquery handles it, thankfully).

I agree that DOM stuff has been inconsistent, and I totally understand why JavaScript has a bad reputation, it's just that the language itself (as opposed to the DOM interaction stuff) is actually really nice, and things like node.js are showing what it can do when separated from the browser.

Just to reinforce what Caer's saying - the reason for that book is to counter the bad attitude towards JavaScript.

If you take browsers and DOMs out of the picture, it's a rather nice language.

It's certainly not perfect - with crappy date handling, dodgy things like boolean objects, and so on - but it's generally no worse than any other language around today.

Lots of things. The fact that it's spelt JavaScript with the capital S for one. There are also lots of things I like about it that I wish other languages had, like closures / anonymous functions.

But the cross-platform compatibility even when using JQuery is a still more work than it should be. Without it, it's a fucking nightmare. And I'm not just talking DOM access / manipulation here. There are many, many more things that you remain blissfully unaware of until you start writing better JavaScript code, then suddenly you have to fight to make things work.

If ECMA International had complete control of the runtime interpreter that browsers and other platforms use to run JavaScript code, the same way only the PHP Group provide the runtime interpreter for PHP code and Sun Oracle provide the JVM for Java it would be 20 billion times better.

It's a sad state of affairs that such a powerful language requires libraries like JQuery and tools like jslint to make it work.

If you take DOMs out of the picture it's not really a language that's used though. I mean, that is 99.9% of its use. Any discussion of JS where you ignore the DOM is not really a meaningful discussion of JS.

Any discussion of JavaScript where you limit yourself to DOMs is stuck in the 90s.

 

* Flash's ActionScript is JavaScript without a DOM.
* Mozilla Rhino is a JavaScript engine for the JVM - no DOM.
* node.js which Caer mentioned is a servery thing without a DOM.
* Qt (the desktop GUI framework) uses JavaScript as a general purpose language.
* Unity (3D game engine) supports JavaScript for game programming.

 

There's plenty of others I wasn't even aware of - OpenOffice and Photoshop both allow scripting with it, and numerous other minor things all use it.

 

It's probably is still >99.9% used by browsers (even though I'm sure that's not a remotely scientific statistic :P ), but non-browser use has definitely been growing these past few years.

Flash's ActionScript is ActionScript. They are both ECMA-based but they are siblings and not parent/child.

Mozilla's Rhino is what? Never heard of it.

Server side JS is a silly idea. Not an inherently bad idea. Just... why another C-like scripting language on the server? Like there's not enough.

Qt uses fucking everything as a general purpose language. May as well say I can use JS as a scripting language in Unity. Which I can. But I can also use Python, C# or Boo.

Oh, you did say that (genuinely hadn't read that far yet).

They're still minority uses. The vast majority of JS ever written is DOM stuff. That is its primary use. Oh right, you said that too. What the fuck are you arguing with me for?

I'm not saying limit the discussion to the DOM. I'm saying acknowledge that that accounts for the massive majority of usage and that any other use is niche, at best.

(I'm not actually asking what Rhino is. I don't care. Partly because I don't care and partly because Mozilla won't be around as a browser much longer the way Chrome is growing)

(I still use FF :$ )

lol @ U Anthony Anthony Thomas.

*Anthony Joseph Thomas

 

But I don't use the Joseph since it's just a confirmation name, and my parents thought my name was badass enough not to need a middle name at birth.... Andrew James.

Andrew James Francis if we're including confirmation names :D

JavaScript is so much more than just another C-like scripting language.

It shares (more-or-less) the brace-based syntax, but JS is functional and prototype-based, neither of which C is (nor its crappy successors).

C++, C#, Java and PHP all implement stupid class-based OO (which I hope the world will eventually realise is a big turd), and everyone who has experienced first-class functions, closures, etc wishes their own language had those features.

Unity uses JavaScript as its primary language - it's what the docs are written for. (Whilst C# and Boo are two alternatives.)

Similarly, Qt might provide connectors for everything under the sun, but its default/internal scripting language is JavaScript.

People are starting to use JavaScript outside of browsers because of the realisation that it's a reasonable language and that it shouldn't be held responsible for the mess the retarded browser manufacturers made of things.

And that's why I'm arguing with you - just because 99.9% of JS involves the DOM doesn't mean that JS is tied to it. It's only a niche at the moment, but it's a growing one, and in a few more years it'll probably be as popular off the DOM as on it.


Oh and Chrome is not going to displace Firefox.

Might end up with a bigger market share, but it's certainly not going to kill it off.

WTF? "Joseph" and "James Francis"? Is that it?

Fucking Lightweights.

I got more middle names than both of you put together. :P