编辑脚本以包括订单总计复选框

我有这个脚本：

//CODE BELOW THIS POINT IS NOT MINE//
/* This script is Copyright (c) Paul McFedries and 
Logophilia Limited (http://www.mcfedries.com/).
Permission is granted to use this script as long as 
this Copyright notice remains in place.*/
function CalculateTotal(frm) {
var order_total = 0
// Run through all the form fields
for (var i=0; i < frm.elements.length; ++i) {
    // Get the current field
    form_field = frm.elements[i]
    // Get the field's name
    form_name = form_field.name
    // Is it a "product" field?
    if (form_name.substring(0,4) == "PROD") {
        // If so, extract the price from the name
        item_price = parseFloat(form_name.substring(form_name.lastIndexOf("_") + 1))
        // Get the quantity
        item_quantity = parseInt(form_field.value)
        // Update the order total
        if (item_quantity >= 0) {
            order_total += item_quantity * item_price
    //My attempt at updating order total for checkbox
           if(document.checkbox.select[i].checked)  
        {
            order_total = item_price
       }
        }
    }
}
// Display the total rounded to two decimal places
frm.TOTAL.value = round_decimals(order_total, 2)
}
function round_decimals(original_number, decimals) {
var result1 = original_number * Math.pow(10, decimals)
var result2 = Math.round(result1)
var result3 = result2 / Math.pow(10, decimals)
return pad_with_zeros(result3, decimals)
 }
function pad_with_zeros(rounded_value, decimal_places) {
// Convert the number to a string
var value_string = rounded_value.toString()
// Locate the decimal point
var decimal_location = value_string.indexOf(".")
// Is there a decimal point?
if (decimal_location == -1) {
    // If no, then all decimal places will be padded with 0s
    decimal_part_length = 0
    // If decimal_places is greater than zero, tack on a decimal point
    value_string += decimal_places > 0 ? "." : ""
}
else {
    // If yes, then only the extra decimal places will be padded with 0s
    decimal_part_length = value_string.length - decimal_location - 1
}
// Calculate the number of decimal places that need to be padded with 0s
var pad_total = decimal_places - decimal_part_length
if (pad_total > 0) {
    // Pad the string with 0s
    for (var counter = 1; counter <= pad_total; counter++) 
        value_string += "0"
    }
return value_string
}
//CODE ABOVE THIS POINT IS NOT MINE//

你定义一个项目的价格，它的ID是这样的：

    <input type="text" name="PROD_CH_35.00" onChange="CalculateTotal(this.form)">

这是复选框功能代码：

function totalcheckbox() {
document.checkbox.TOTAL.value = ''; //I set the value of all the checkboxes equal to nothing
var total = 0;
//For loop iterates through all the checkboxes. ++ adds one each time to i.
for (i=0;i<document.checkbox.select.length;i++) {
      if (document.checkbox.select[i].checked) {
        total = total + parseInt(document.checkbox.select[i].value); //take whatever they selected and make it into an integer
      }
    }
document.checkbox.TOTAL.value = total; //total value box equal to the sum
}

我的复选框是这样的：

    <input type="checkbox" name="select" value="15" onchange="totalcheckbox()">

我遇到的问题是其中两个字段是复选框。我想要它，所以当我选中这些复选框时，它将添加到订单总额中。当我取消选中复选框时，它将减去复选框的价格。

例如，我可以有一个这样的复选框：

    <input type="checkbox" name="PROD_CH_15.00" value="15" onchange="totalcheckbox()">

复选框的函数本身可以添加总计，订单总计函数也可以工作。最大的问题是编辑订单总计脚本，以便复选框将更改总价，就像您在文本框中输入数量时一样，它将更新总计。

这是工作复选框代码的JS小提琴：http://jsfiddle.net/7uzr4/

这是订单总代码的JS小提琴：http://jsfiddle.net/X2wMR/

如何组合这两个代码，以便复选框代码也添加到订单总额中？