jQuery checkbox and select - sum the values and add in var

Question

The explanation is below the code:

The code for HTML is :

Add-ons


        
      

Answer 1

JsFiddle

HTML:

Add-ons
Add-on Number 1 - 10 QR 

Add-on Number 2 - 20 QR 

Add-on Number 3 - 40 QR 

Add-on Number 4 - 60 QR 



 I want more add-ons

    0
    1
    2
    3


 User total usage:  

Javascript:

function displayVals() {
      calcUsage();
      var singleValues = $("#more").val();         
      $("#span").html("more addons: " + 
                  singleValues + ' QR');
}
var $cbs = $('input[name="ch1"]');
function calcUsage() {
    var total = $("#more").val();
    $cbs.each(function() {
        if (this.checked)
            total = parseInt(total) + parseInt(this.value);
    });
    $("#usertotal").text(total + ' QR');
}

    $("select").change(displayVals);
    displayVals();
//For  checkboxes

$cbs.click(calcUsage);