Radio and Checkbox Checked Values Won't Show in JavaScript

I'm trying to get the value of a radio button and multiple checkboxes to appear in a new window using JavaScript. I can't seem to figure out why "true" return instead of the actual value checked. Below is the code and screenshot of the results.

function messagebox()
{
        var newWindow;
        var msg ="";
        var i = document.PizzaForm.state.options.selectedIndex;
        var text = document.PizzaForm.state.options[i].text;
        var value = document.PizzaForm.state.options[i].value;
        
        { document.PizzaForm.customer.value = document.PizzaForm.customer.value.replace(/\w\S*/g, function(txt){return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();}); }
        
        { document.PizzaForm.city.value = document.PizzaForm.city.value.replace(/\w\S*/g, function(txt){return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();}); }
        
        newWindow = window.open("","","status=no,height=500,width=500");
        message = "<ul><li>Name: " + document.PizzaForm.customer.value;
    message += "<li>Address: " + document.PizzaForm.address.value;
    message += "<li>City: " + document.PizzaForm.city.value;
    message += "<li>State: " + document.PizzaForm.state.value;
    message += "<li>Zip Code: " + document.PizzaForm.zip.value;
    message += "<li>Phone: " + document.PizzaForm.phone.value;
    message += "<li>Email: " + document.PizzaForm.email.value;
        message += "<li>Size: " + showSize();
        message += "<li>Toppings: " + showToppings();
        newWindow.document.write(message);

function showSize()
        {
        for(i=0;i<document.PizzaForm.sizes.length;i++)
        if(document.PizzaForm.sizes[i].checked)
                msg += document.PizzaForm.sizes[i].value;
        return true;
        }
        
function showToppings()
        {
        for(i=0;i<document.PizzaForm.toppings.length;i++)
        if(document.PizzaForm.toppings[i].checked)
            msg += (i==0?"":",")+document.PizzaForm.toppings[i].value;
        return true;
        }       
}