First, pass event reference into input change:
<input type="file" change="change( e )" hidden>
Second, retrieve the name from event target:
function change( e ) {
const files = e.target.files;
const file = files[0];
const file_name = file.name;
}
Read some docs on input file. Such as this @Mozilla.
NOTE:
If you have troubles with the onchange event, assign some id to your input, perhaps like this:
<input type="file" id="file_input">
and then query for the element by that id, like this:
document.getElementById('file_input').onchange = function( e ) {
const files = e.target.files;
const file = files[0];
const file_name = file.name;
alert(file_name);
}