JSFiddle - React, Tailwind, and code Playground
HTML
<div id="class-1" class="classes">
<input type="text" id="name-class-1" />
<input type="text" id="number-class-1" />
<input type="text" id="book-class-1" />
</div>
<input type="button" id="add" value="add"/>
JavaScript
$("#add").click(function (e) {
var amount = $('div.classes').length;
var new_amount = amount + 1;
var cloned_div = $('#class-' + amount).clone();
cloned_div.insertAfter('#class-' + amount);
cloned_div.find('[id$="-' + amount + '"]').andSelf().each(function(index, child) {
child.id = child.id.replace("-" + amount, "-" + new_amount);
});
});