Spinner value not updated?

Spinner value not updated?

Hi, I'm using spinner widget for the first time.

I have a number of text fields width numerical value.

For every input field I have a spinner.

Everething work fine when I submit the form, but I have a strange behaviour when looking in the source code with firebug:

  1. <input type="text" value="12" name="prop[70]" class="size ui-spinner-input" aria-valuemin="0" aria-valuemax="100" aria-valuenow="13" autocomplete="off" role="spinbutton">
A the time I'm looking at my code, I can see in the text field the value "13", but the value attribute is "12".

In the form I want to be able (if a checkbox is selected) to update all the fields with the same value in change event.

This works the first time, then when I try to select all input fileds with value of 13 I can't find anything cause the value attribute is set to 12.

Any suggestion? 

Thank you.