maybe something like this:
var totalFields = <?=$total_fields?>;
var currentFields = 0;
var addMode = document.getElementById('addMore');
var form = docuement.getElementsByTagName('form')[0];
addMore.onclick = function() {
if (currentFields >= totalFields) {
return false;
}
var newField = document.createElement('input');
newField.setAttribute('type', 'file');
newField.setAttribute('name', 'file'+currentFields);
form.appendChild(newField);
currentFields++
}
and then
<?
foreach ($_FILES as $file) {
// i guess you know what you should do
}
?>
not tested … just for example
solved How to create more form fields by using javascript and then passing values to PHP