[development] Form API and Javascript stuck

Karyn Cassio karyn at karyncassio.com
Mon Feb 22 00:43:24 UTC 2010

Alrighty, now I'm home and actually looking at the code surrounded by 
I assume the code below (with modifications of course) should be 
replacing my javaScript code.
However, I'm not sure how I call this from my form.
I was calling the javascript with an onchange attribute of a textfield.
(BTW, all Earl's assumptions below were exactly correct.)

The name of my module is compute_items. This is how I stated the jquery 
Drupal.behaviors.compute_items = function() {
//code stuff

Is that the right direction?


On 2/21/10 2:22 PM, Earl Miles wrote:
> Karyn Cassio wrote:
>> Hi Everyone,
>> I hope you are enjoying your weekend and not working too hard.
>> I'm still trying to get my head around js, and was hoping someone may 
>> have some insights to help me with the next steps on a form I am 
>> creating.
>> I have an order form that is going to be dynamically created.
>> I am able to successfully pass the quantity value upon user input for 
>> field 1.
>> Basically I'm using onchange() to pass the quantity value to the script.
>> The id of the price field is of the format unit-price-0, 
>> unit-price-1, etc.
>> Each line item's subtotal should update before going onto the next 
>> line item.
>> Here's the js function. Each line item has its own unit-cost, 
>> quantity, and subtotal.
>> Any help would be so appreciated.
> Let's assume that you've set up the ids so that they all match:
> 1) Each line item has a unique, probably numeric id.
> 2) The id of all the form fields for each line item is carefully
>    crafted such that the quantity will be "edit-quantity-ID", the
>    price will be "edit-price-ID" and the subtotal will be
>    "edit-subtotal-ID"
> 3) The quantity is a textfield. The price is either a disabled textfield
>    so that the user cannot change it, or a hidden field. The subtotal
>    is similar.
> 4) Each line item quantity has this class: 'line-item-quantity'.
> You would then create a .js file using this code. Note that I am using 
> jQuery to create simpler code, so if you're not familiar with jQuery 
> it may not be immediately understandable, but it would be very 
> valuable to learn some as use of jQuery significantly increases 
> javascript productivity.
> For example's sake I am butchering the calculation to be as simple as 
> possible. Judging from your code it needs to be a touch more complex 
> than this, but you can handle that I am sure.
> ----
> // You would put this inside a Drupal behavior:
> Drupal.behaviors.myBehaviorFunction = function() {
>   $('.line-item-quantity:not(.line-item-processed)')
>     .addClass('line-item-processed') // Ensures we do only process once
>     .change(function() {
>       // The id of this should be edit-quantity-ID so we use replace
>       // to get the base id:
>       var id = $(this).attr('id').replace('edit-quantity-', '');
>       var price = $('edit-price-' + id).val();
>       var subTotal = id * price; // Do your actual calculation here.
>       $('edit-subtotal-' + id).val(subTotal);
>     });
> };

Karyn Cassio
Drupal Developer

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