JSFiddle - React, Tailwind, and code Playground

HTML

<select size='1' id="a" name='a'>
  <option value="None" selected>choices</option>
  <option value='1'>first</option>
  <option value='2'>second</option>
</select>

<input type="input" name="whatever" value="test">

<input type="button" id="resetvalues" value="Reset values">

JavaScript

var DefaultValuesElements=$(":input").not("#resetvalues");  // The elements you want to reset

function getDefaultValues() {
  DefaultValuesElements.each(function() {
    $(this).attr("defaultvalue",$(this).val());
  });
}

function setDefaultValues() {
  DefaultValuesElements.each(function() {
    $(this).val($(this).attr("defaultvalue"));
  });
}

getDefaultValues();

$("#resetvalues").click(function() {
  setDefaultValues();
});