How to trigger bootstrap toast ? other then button type=”button”, or fetch()

Is there a simple, other solution to trigger my boostrap toast ?
Maybe like :
button onclick ="trigger my bootstrap toast the easy way"
Without the need of fetch or a button type=”button”.
I think i have overseen a simple way to implenet it.

My sitecode looks like :

<form> <button=type"submit" name="need the name for my json key" value="need you also for my json"
To my PHP background app, to save my value to json strings in a file.
Is there any simpler way to implement the call to trigger bootstrap toast?
The PHP background side is not the problem, I just want to POST my values to my PHP.