// TITLE: Order Form with Checkbox and Radio Button Item Selection
	// An order form which utilizes checkboxes AND radio buttons for making a selection. The
	//   checkbox only allows one quantity of any item to be ordered, while the radio button
	//   only allows for one item within a defined group to be ordered.
	// Script updates the order total as the visitor makes his/her selections.
	// Also note that the order total can not be manually altered by the visitor.

	// Custom scripting by Paul DeBrino of Infinity Research and Development, Inc.
	// We also have a netscrape version for purchase, which works with both NS and IE.
	// For other scripts, or to place an order for customized scripts such as
	//   on-line form scripting, please contact the owner via the contact form at infinity-rd.com
	// If you wish to use this script, kindly keep these comments and (C)opyright within the
	//   source code.  Permission granted for http://javascript.internet.com to publish this script.

	//Define function to manipulate the form total per item selected/deselected:
	function CheckChoice(whichbox)
	{
		with (whichbox.form)
		{

			{
				//If box was checked, accumulate the checkbox value as the form total,
				//Otherwise, reduce the form total by the checkbox value:
				if (whichbox.checked == false)
					{ hiddentotal.value = eval(hiddentotal.value) - eval(whichbox.value); }
				else 	{ hiddentotal.value = eval(hiddentotal.value) + eval(whichbox.value); }
			}

			//Ensure the total never goes negative (some browsers allow radiobutton to be deselected):
			if (hiddentotal.value < 0)
				{
				InitForm();
				}

			//Now, return with formatted total:
			return(formatCurrency(hiddentotal.value));
		}
	}

	//Define function to format a value as currency:
	function formatCurrency(num)
	{
	   // Courtesy of http://www7.brinkster.com/cyanide7/
		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);
	}

	//Define function to init the form on reload:
	function InitForm()
		{
		//Reset the displayed total on form:
		document.myForm.total.value='£0';
		document.myForm.hiddentotal.value=0;

		//Set all checkboxes on form to unchecked:
		for (xx=0; xx < document.myForm.elements.length; xx++)
		{
		   if (document.myForm.elements[xx].type == 'checkbox')
			{
			document.myForm.elements[xx].checked = false;
			}
		}

	}