How to trigger a file download when clicking an HTML button or JavaScript

Question

This is crazy but I don\'t know how to do this, and because of how common the words are, it\'s hard to find what I need on search engines. I\'m thinking this should be an ea

Answer 1

This is what finally worked for me since the file to be downloaded was determined when the page is loaded.

JS to update the form's action attribute:

function setFormAction() {
    document.getElementById("myDownloadButtonForm").action = //some code to get the filename;
}

Calling JS to update the form's action attribute:

Form tag with the submit button:

    Click to open document:  
    Open Document

The following did NOT work: