Javascript checkbox onChange

Question

I have a checkbox in a form and I\'d like it to work according to following scenario:

• if someone checks it, the value of a textfield (totalCost)

Answer 1

Reference the checkbox by it's id and not with the # Assign the function to the onclick attribute rather than using the change attribute

var checkbox = $("save_" + fieldName);
checkbox.onclick = function(event) {
    var checkbox = event.target;

    if (checkbox.checked) {
        //Checkbox has been checked
    } else {
        //Checkbox has been unchecked
    }
};