// mredkj.com
// OrderForm.js - v0.4
// v0.4 - 2007-02-01
// v0.3 - 2006-04-09
// v0.2 - 2006-04-08
// v0.1 - 2006-04-06

function OrderForm(prefix, precision, firstChoice) {
	
	this.prefix = prefix ? prefix : '';
	
	// ****************************
	// Configure here
	// ****************************
	// names - Set these according to how the html ids are set
	this.FORM_NAME = this.prefix + 'frmOrder';
	this.BTN_TOTAL = this.prefix + 'btnTotal';
	this.TXT_OUT = this.prefix + 'txtTotal';
	
	// partial names - Set these according to how the html ids are set
	this.CHK = this.prefix + 'chk';
	this.SEL = this.prefix + 'sel';
	this.PRICE = this.prefix + 'txtPrice';
	
	// precision for the decimal places
	// If not set, then no decimal adjustment is made
	this.precision = precision ? precision : -1;
	
	// if the drop down has the first choice after index 1
	// this is used when checking or unchecking a checkbox
	this.firstChoice = firstChoice ? firstChoice : 1;
	// ****************************
	
	// form
	this.frm = document.getElementById(this.FORM_NAME);
	
	// checkboxes
	this.chkReg = new RegExp(this.CHK + '([0-9]+)');
	this.getCheck = function(chkId) {
		return document.getElementById(this.CHK + chkId);
	};
	
	// selects
	this.selReg = new RegExp(this.SEL + '([0-9]+)');
	this.getSelect = function(selId) {
		return document.getElementById(this.SEL + selId);
	};
	
	// price spans
	this.priceReg = new RegExp(this.PRICE + '([0-9]+)');
	
	// text output
	this.txtOut = document.getElementById(this.TXT_OUT);
	
	// button
	this.btnTotal = document.getElementById(this.BTN_TOTAL);
	
	// price array
	this.prices = new Array();
	
	var o = this;
	this.getCheckEvent = function() {
		return function() {
			o.checkRetotal(o, this);
		};
	};
	
	this.getSelectEvent = function() {
		return function() {
			o.totalCost(o);
		};
	};
	
	this.getBtnEvent = function() {
		return function() {
			o.totalCost(o);
		};
	};
	
	/*
	 * Calculate the cost
	 * 
	 * Required:
	 *  Span tags around the prices with IDs formatted
	 *  so each item's numbers correspond its select elements and input checkboxes.
	 */
	this.totalCost = function(orderObj) {
		var spanObj = orderObj.frm.getElementsByTagName('span');
		var total = 0.0;
		for (var i=0; i<spanObj.length; i++) {
			var regResult = orderObj.priceReg.exec(spanObj[i].id);
			if (regResult) {
				var itemNum = regResult[1];
				var chkObj = orderObj.getCheck(itemNum);
				var selObj = orderObj.getSelect(itemNum);
				var price = orderObj.prices[itemNum];
				var quantity = 0;
				if (selObj) {
					quantity = parseFloat(selObj.options[selObj.selectedIndex].text);
					quantity = isNaN(quantity) ? 0 : quantity;
					if (chkObj) chkObj.checked = quantity;
				} else if (chkObj) {
					quantity = chkObj.checked ? 1 : 0;
				}
				total += quantity * price;
			}
		}
		if (this.precision == -1) {
			orderObj.txtOut.value = total
		} else {
			orderObj.txtOut.value = total.toFixed(this.precision);
		}
	};

	/*
	 * Handle clicks on the checkboxes
	 *
	 * Required:
	 *  The corresponding select elements and input checkboxes need to be numbered the same
	 *
	 */
	this.checkRetotal = function(orderObj, obj) {
		var regResult = orderObj.chkReg.exec(obj.id);
		if (regResult) {
			var optObj = orderObj.getSelect(regResult[1]);
			if (optObj) {
				if (obj.checked) {
					optObj.selectedIndex = orderObj.firstChoice;
				} else {
					optObj.selectedIndex = 0;
				}
			}
			orderObj.totalCost(orderObj);
		}
	};
	
	/*
	 * Set up events
	 */
	this.setEvents = function(orderObj) {
		var spanObj = orderObj.frm.getElementsByTagName('span');
		for (var i=0; i<spanObj.length; i++) {
			var regResult = orderObj.priceReg.exec(spanObj[i].id);
			if (regResult) {
				var itemNum = regResult[1];
				var chkObj = orderObj.getCheck(itemNum);
				var selObj = orderObj.getSelect(itemNum);
				if (chkObj) {
					chkObj.onclick = orderObj.getCheckEvent();
				}
				if (selObj) {
					selObj.onchange = orderObj.getSelectEvent();
				}
				if (orderObj.btnTotal) {
					orderObj.btnTotal.onclick = orderObj.getBtnEvent();
				}
			}
		}
	};
	this.setEvents(this);

	/*
	 *
	 * Grab the prices from the html
	 * Required:
	 *  Prices should be wrapped in span tags, numbers only.
	 */
	this.grabPrices = function(orderObj) {
		var spanObj = orderObj.frm.getElementsByTagName('span');
		for (var i=0; i<spanObj.length; i++) {
			if (orderObj.priceReg.test(spanObj[i].id)) {
				var regResult = orderObj.priceReg.exec(spanObj[i].id);
				if (regResult) {
					orderObj.prices[regResult[1]] = parseFloat(spanObj[i].innerHTML);
				}
			}
		}
	};
	this.grabPrices(this);
	
}


<!-- Paste this code into an external JavaScript file  -->

/* This script and many more are available free online at
The JavaScript Source :: http://javascript.internet.com
Created by: Kevin Hartig :: http://www.grafikfx.net/ */

// Calculate the total for items in the form which are selected.
function calculateTotal(inputItem) {
  with (inputItem.form) {
    // Process each of the different input types in the form.
    if (inputItem.type == "radio") {   // Process radio buttons.
      // Subtract the previously selected radio button value from the total.
      calculatedTotal.value = eval(calculatedTotal.value) - eval(previouslySelectedRadioButton.value);
      // Save the current radio selection value.
      previouslySelectedRadioButton.value = eval(inputItem.value);
      // Add the current radio button selection value to the total.
      calculatedTotal.value = eval(calculatedTotal.value) + eval(inputItem.value);
    } else {   // Process check boxes.
      if (inputItem.checked == false) {   // Item was uncheck. Subtract item value from total.
          calculatedTotal.value = eval(calculatedTotal.value) - eval(inputItem.value);
      } else {   // Item was checked. Add the item value to the total.
          calculatedTotal.value = eval(calculatedTotal.value) + eval(inputItem.value);
      }
    }

    // Total value should never be less than 0.
    if (calculatedTotal.value < 0) {
      InitForm();
    }

    // Return total value.
    return(formatCurrency(calculatedTotal.value));
  }
}

// Format a value as currency.
function formatCurrency(num) {
  num = num.toString().replace(/\$|\,/g,'');
  if(isNaN(num))
     num = "0";
  sign = (num == (num = Math.abs(num)));
  num = Math.floor(num*100+0.50000000001);
  cents = num%100;
  num = Math.floor(num/100).toString();
  if(cents<10)
      cents = "0" + cents;
  for (var i = 0; i < Math.floor((num.length-(1+i))/3); i++)
      num = num.substring(0,num.length-(4*i+3)) + ',' + num.substring(num.length-(4*i+3));
  return (((sign)?'':'-') + '$' + num + '.' + cents);
}

// This function initialzes all the form elements to default values.
function InitForm() {
  // Reset values on form.
  document.selectionForm.total.value='$0';
  document.selectionForm.calculatedTotal.value=0;
  document.selectionForm.previouslySelectedRadioButton.value=0;

  // Set all checkboxes and radio buttons on form to unchecked.
  for (i=0; i < document.selectionForm.elements.length; i++) {
    if (document.selectionForm.elements[i].type == 'checkbox' | document.selectionForm.elements[i].type == 'radio') {
      document.selectionForm.elements[i].checked = false;
    }
  }
}


function MM_findObj(n, d) { //v4.01
  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
  if(!x && d.getElementById) x=d.getElementById(n); return x;
}

function MM_validateForm() { //v4.0
  var i,p,q,nm,test,num,min,max,errors='',args=MM_validateForm.arguments;
  for (i=0; i<(args.length-2); i+=3) { test=args[i+2]; val=MM_findObj(args[i]);
    if (val) { nm=val.name; if ((val=val.value)!="") {
      if (test.indexOf('isEmail')!=-1) { p=val.indexOf('@');
        if (p<1 || p==(val.length-1)) errors+='- '+nm+' must contain an e-mail address.\n';
      } else if (test!='R') { num = parseFloat(val);
        if (isNaN(val)) errors+='- '+nm+' must contain a number.\n';
        if (test.indexOf('inRange') != -1) { p=test.indexOf(':');
          min=test.substring(8,p); max=test.substring(p+1);
          if (num<min || max<num) errors+='- '+nm+' must contain a number between '+min+' and '+max+'.\n';
    } } } else if (test.charAt(0) == 'R') errors += '- '+nm+' is required.\n'; }
  } if (errors) alert('The following error(s) occurred:\n'+errors);
  document.MM_returnValue = (errors == '');
}