I have the following coding in my website that add's or remove's prices to a quote page and works perfect but I need to insert another input field that takes the order total and divides it by 2

Just wondering how I do that in this coding

Below is the HTML

<form name="checkbox"> One Page<input type="checkbox" name="PROD_CH_70.00" value="70" onchange="CalculateTotal(this.form)"> <br> Two Pages<input type="checkbox" name="PROD_CH_140.00" value="140" onchange="CalculateTotal(this.form)"> <br> Three Pages(Bronze Package)<input type="checkbox" name="PROD_CH_179.00" value="179" onchange="CalculateTotal(this.form)"> <br> Six Pages(Silver Package)<input type="checkbox" name="PROD_CH_339.00" value="339" onchange="CalculateTotal(this.form)"> <br> Ten Pages(Gold Package)<input type="checkbox" name="PROD_CH_549.00" value="549" onchange="CalculateTotal(this.form)"> <br> New Business Start up<input type="checkbox" name="PROD_CH_289.00" value="289" onchange="CalculateTotal(this.form)"> <br> Ecommerce Package<input type="checkbox" name="PROD_CH_449.00" value="449" onchange="CalculateTotal(this.form)"> <br> SEO on all pages<input type="checkbox" name="PROD_CH_30.00" value="449" onchange="CalculateTotal(this.form)"> <br> Logo Design<input type="checkbox" name="PROD_CH_25.00" value="25" onchange="CalculateTotal(this.form)"> <!--<input type="text" name="PROD_DC_15" size="10" maxlength="3" onchange="CalculateTotal(this.form)"> <input type="text" name="PROD_CC_20" size="10" maxlength="3" onchange="CalculateTotal(this.form)">--> <br><br> <span style="color: #FFFFFF;">£<input type="text" name="TOTAL" size="10" onfocus="this.form.elements[0].focus() "> </span> </form>

Below is the javascript coding

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 if(form_field.type == 'checkbox') { item_quantity = form_field.checked; } else { item_quantity = parseInt(form_field.value); } // Update the order total if (item_quantity >= 0) { order_total += item_quantity * 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 }