Looking for a simple(?) calculation script

I'm looking for what I think is probably a simple javascript calculation form for a web page.
It looks like this:

---------------------------
Item 1 [Fixed Value] [User Input ] [Fixed Value*User Input]
Item 2 [Fixed Value] [User Input] [Fixed Value*User Input]
Item 3 [Fixed Value] [User input] [Fixed Value*User Input]

[Sum of all (Fixed Value*User Input)]
----------------------------

The only variable supplied by the user would be [User input]. Everything else would be fixed or calculated. [User Input] should default to zero. The 'Sum of" line is very important.

I don't care if it calculates dynamically or if you have to hit a "submit" button, but the calculations need to appear on the same page as the input form so that the user can make changes easily multiple times after seeing the results.

I have found some spreadsheet and calculator templates, but so far they do either waaay too much or not enough.

If anyone can point me to a template, specific tutorial, or have some spare code lying about, I'd be forever grateful. I am javascript illiterate, but if I have the guts I can teach myself how to tweak it from there. Thanks!

 

Try these, if you need help to customise them just ask.

http://javascript.internet.com/forms/confirm-order.html
http://javascript.internet.com/forms/order-form.html
http://javascript.internet.com/forms/update-order-form-no-page-refresh.html

 

Thanks. That's the general idea, especially the all-on-one-page.

But rather than checkbox selection, I need the user to be able to input a quantity into a text field, because the quantity can vary quite a bit from item to item.

 

Basically you would need to change <input type="checkbox" to <input type="text" and use onfocus instead of onclick to call the script when the user enters the data in the text box.

The basic syntax for adding up the totals will be:

item1.value=fixedvalue.value * item1.value;
item2.value=fixedvalue.value * item2.value;
finaltotal.value = eval(item1.value) + eval(item2.value);

Code (markup):

Don't forget to use a hidden variable for fixedvalue.

 

Thanks, mad4. I'll wrestle with it and see how far I get.