Autocomplete: How can I post the value of ui.item.id to php

Autocomplete: How can I post the value of ui.item.id to php

How can I post the value of ui.item.id to the php-script that creating the web-page?

Example:
I am using Autocomplete for a input field named "bankcode".

After I select the correct "bankcode" I get back as result from the source search.php the
name of the bank as "ui.item.id", too.

Now, I want to post the value of ui.item.id (name of the bank) to the script BankDataInput.php,
that controlls the whole page.

What I have to do ?

Many thanks in advance.