Forms. How can I send a hidden parameter to a form in SaveItem (for example, a Cookie or URL parameter)

To do this, use special types of form columns - cookie, localStorage, sessionStorage, and urlParameter

They will not be visible on the page (these are the input[type=hidden] fields). The key name is passed to them as a value on the form (the key name matches the field code).

When saving a form to SaveItem, the value for this key is passed from the corresponding storage. 

Falcon Space is a functional web development platform on a narrow stack MS SQL/Bootstrap. Falcon Space Gettting started

SQL-tool for creating personal accounts on the site

The essence of the approach and the history of the creation of Falcon Space
Web platform for creating personal accounts

Falcon Space Platform

This is a reduction in the cost of ownership

at the expense of fewer people to support

This is a quick change

while using the program

This is a modern interface

full adaptation for mobile devices

MS SQL web applications. Affiliate program for developers and web studios

You can develop on your own or collaborate with us on Falcon Space web development using only SQL and HTML.
See examples with SQL code
Platform documentation
Working on MS SQL Server