JSFiddle - React, Tailwind, and code Playground

by gregborbonus

HTML

<select class="form-control-2 box3 mySelectBox" id="optionTaglioLungo">
  <option value="0">INSERIRE PREZZO</option>
  <option value="1">A PARTIRE DA</option>
  <option value="2">PREZZO DA_ A_ </option>
</select>
<select class="form-control-2 box3 mySelectBox" id="optionTaglioCorto">
  <option value="0">INSERIRE PREZZO</option>
  <option value="1">A PARTIRE DA</option>
  <option value="2">PREZZO DA_ A_ </option>
</select>
<select class="form-control-2 box3 mySelectBox" id="optionTaglioMedio">
  <option value="0">INSERIRE PREZZO</option>
  <option value="1">A PARTIRE DA</option>
  <option value="2">PREZZO DA_ A_ </option>
</select>

<a href="javascript:void(0);" onclick="alert_me();">TEST ME</a>

JavaScript

$(document).ready(function() {
      $(function() {
        $('select').on('change', function() {

          var mySelectBox = $(this);
          var mySelectBoxId = mySelectBox.attr('id');
          var myOption = $(this).val();
          gvar = mySelectBoxId; //Global, can be used outside the function.


          console.log(mySelectBoxId); //This is defined.
        });
      });
    });

    function alert_me() {
      if (typeof gvar == "undefined")
        alert('You\'ve not used any dropdown');
      else
        alert(gvar);
      if (typeof mySelectBoxID == "undefined") mySelectBoxId = "undefined";
      alert('See, I\'m not defined: ' + mySelectBoxId);
    }