hx-include
The hx-include attribute allows you to include additional element values in an AJAX request. The value of this attribute is a CSS query selector of the element or elements to include in the query.
Here is an example that includes a separate input value:
<div>
<button hx-post="/register" hx-include="[name='email']">
Register!
</button>
Enter email: <input name="email" type="email"/>
</div>
This is a little contrived as you would typically enclose both of these elements in a form and submit the value automatically, but it demonstrates the concept.
Note that if you include a non-input element, all input elements enclosed in that element will be included.
Notes
hx-include is inherited and can be placed on a parent element
[HTMX Reference](https://htmx.org/attributes/hx-include/)