JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" name="name" value='1'> 1
<input type="checkbox" name="name" value='2'> 2
<input type="checkbox" name="name" value='3'> 3
<input type="checkbox" name="name" value='4'> 4

<button>Fetch Values</button>

JavaScript

$(function () {
    $('button').click(function () {
       var csv = '';    
       $('input:checkbox:checked').each(function (i) {
           csv+= this.value + ',';
     
          var truncated = str.substring(0, csv.length - 1);
           alert(truncated);
           }); 
       
    });
       
    });
});