Use function within ajax Response Success

Question

I have a list of tasks with checkboxes, which when marked updates, via ajax, the status of the task in the database, what I want to do is return the completion percentage of the list, which is already done in the backend, and also already has a function js called "percentage", the problem is that in checkbox marking Success I would like to take the value of the percentage function, but there is no return.

Ex:

function porcentagem(id) {

    $.ajax({
        url: 'url',
        method:'POST',
        dataType: 'JSON',
        data: {id: id},
        success: function(data) {
            if(data.success == 1) {
                return data.porcentagem;
            }
        }

    });
}

Success: ajax of the checkbox:

                if(data.success == 1) {
                    var id = $("input[name='id']").val();
                    alert( porcentagem(id) );
                }

The percentage function was set before ajax, and yet the console shows me:

Uncaught Typeerror: percentage is not a Function