Javascript to clear multiple fields

Javascript to clear multiple fields

I'm trying to figure out what is probably a simple script but I'm really
bad at js.
I have a button that I want to reset fields that are dynamically created.
<button type="reset" onclick="clearDiv_<?php echo $mid; ?>();"><?php echo
$reset ?></button>
I have a script attached to each field
function clearDiv_<?php echo $mid; ?>() {
var t = '<?php echo $id.'_output'; ?>';
var getDiv = document.getElementById( t );
var emptyDiv = getDiv.innerHTML = "";
}
Basically each field is assigned a group ID ($mid). The $id is the
individual field ID. Looking at the outputted HTML it looks like it should
clear all of the fields but it's only clearing the last field in the
group. How can I make it work and trigger each of the fields the script is
attached to?