Code for Computer price sheet

[jeff_okeeffe]

I'm currently building a webpage with javascript with numerous computer parts where a customer can choose parts to suit thier needs for a computer system. I have it set up so they click a check box in each category e.g processors, memory etc which then adds up a total price. I dont have a problem getting prices to add up when the checkboxes are checked but i need an error checking script so that they can only choose 1 item in a category for example they can only choose 1 processor and if they try to choose 2 processors i want it so that it spits out an error message like "You can only choose 1 processor". Any suggestions would be greatly appreciated.

[SirDice]

Why don't you use groups of radiobuttons? One group per category..

As for checking.. (pseudocode, simple braindead solution)

a=0;
if (checkbox1) then a++;
if (checkbox2) then a++;
if (checkbox3) then a++;
if a>1 then alert ("greedy hey!");
if a=0 then alert ("hey, pick 1!");

[valhallen]

yup am with SirDice on this I would def go with radio buttons rather than checkboxes. One other point to remember as well is that not only should you be validating the form client side but also server side. Never accept anything from the client is valid when received from a form to your server....no matter how strict your validation routines are in the client.

As client side validation is being done on the users machine they can easily disable javascript or alter form elements (Firefox Webdev Toolbar Extension is just one way of altering actual form elements on the page.)