I want to upgrade magento 2 jQuery version from 1.9 to 3
do you think is an good idea? how i do it for upgrade jquery build-in file who come with magento 2 ?
No. While jQuery 2 just dropped old-IE hacks jQuery 3 introduced some breaking changes.
You can play a bit with jQuery Migrate plugin to see how much the things are broken and what would it look like to migrate Magento 2 to jQuery 3. What is the value such migration would bring?
Just wondering, why somebody would like to use jQuery for such a complicated project as ecommerce system in 2016 at all? :)