Looping through multiple checkboxes and adding the checked values to an array to write back to Sharepoint

I have a block of code that is supposed to look at which checkboxes are checked and then write the value of those checkboxes to an array so that I can write the data back to Sharepoint. I got it working before when I used an if/else statement, but I need it to be able to handle multiple checkboxes being selected. I did some research and found part of my code from another answer and combined it with some of my code but it doesn't seem to be working and I'm not sure why. None of the other answers I came across seem to be what I'm looking for.

Basically, what I'm asking is, what is the best way to achieve what I'm trying to do?

function addCustomers() {
    $(document).ready(function () {
        var customers = [];
        var ckbox = $('.customer-options');

        $('input').on('click', function () {
            if (ckbox.is(':checked')) {
                customers.push(ckbox).val();
            }
            else {
            }
        });

        customers.toString();
        document.getElementById('mxID04').innerHTML = customers;
    });
}