JSFiddle - React, Tailwind, and code Playground

by Lee Cooper

HTML

<input type="checkbox" name="a" value="1" />
<input type="checkbox" name="a" value="2" />
<input type="checkbox" name="a" value="3" />
<input type="hidden" name="b" value="" />

JavaScript

$(function() {
    
    $('input[name="a"]').change(function() {
        console.time('a');
        var val = [];
        
        $('input[name="a"]:checked').each(function(i, item) {
            val.push($(item).val());
        });
        
        $('input[name="b"]').val(val.join(','));
        
        console.timeEnd('a');
        
        console.log($('input[name="b"]').val());
    });
    
});