// JavaScript Document
	function calcROI()
	{
		//wtl_Tag5_151548('action');

		var nANALOG, nISDN30, analog_bt_qtrly, analog_yc_qrtly, isdn30_bt_qtrly, isdn30_yc_qrtly;
		var analog_bt_hid, analog_yc_hid, isdn30_bt_hid, isdn30_yc_hid;
		var analog_yc_100_hid, analog_yc_1000_hid, analog_yc_more_hid;
		var analog_ann_sav, isdn30_ann_sav, total_saving;
		// If either entry boxes are empty, set to 0 to allow the rest of the calculations to work.
		if(!document.forms.roi_calc.analog_no_lines.value){
			document.forms.roi_calc.analog_no_lines.value = "0";
		}
		if(!document.forms.roi_calc.isdn30_no_lines.value){
			document.forms.roi_calc.isdn30_no_lines.value = "0";
		}

		nANALOG = parseInt(document.forms.roi_calc.analog_no_lines.value);
		nISDN30 = parseInt(document.forms.roi_calc.isdn30_no_lines.value);

		if((nANALOG + "") != document.forms.roi_calc.analog_no_lines.value || nANALOG < 0){
		// The values entered aren't positive integers, alert the user and stop calculation.
			alert("Please enter whole, positive numbers only");
			document.forms.roi_calc.analog_no_lines.select();
			return(false);
		}
		
		if((nISDN30 + "") != document.forms.roi_calc.isdn30_no_lines.value || nISDN30 < 0){
		// The values entered aren't positive integers, alert the user and stop calculation.
			alert("Please enter whole, positive numbers only");
			document.forms.roi_calc.isdn30_no_lines.select();
			return(false);
		}
		analog_bt_hid = parseFloat(document.forms.roi_calc.analog_bt_hid.value);
		analog_yc_100_hid = parseFloat(document.forms.roi_calc.analog_yc_100_hid.value);
		analog_yc_1000_hid = parseFloat(document.forms.roi_calc.analog_yc_1000_hid.value);
		analog_yc_more_hid = parseFloat(document.forms.roi_calc.analog_yc_more_hid.value);

		// Calculate the new values
		analog_bt_qtrly = nANALOG * analog_bt_hid;
		analog_yc_qrtly = nANALOG * (nANALOG < 100 ? analog_yc_100_hid  : (nANALOG < 1000 ? analog_yc_1000_hid  : analog_yc_more_hid ));
		analog_ann_sav = (analog_bt_qtrly - analog_yc_qrtly) * 4;

        isdn30_bt_hid = parseFloat(document.forms.roi_calc.isdn30_bt_hid.value);
		isdn30_yc_100_hid = parseFloat(document.forms.roi_calc.isdn30_yc_100_hid.value);
		isdn30_yc_1000_hid = parseFloat(document.forms.roi_calc.isdn30_yc_1000_hid.value);
		isdn30_yc_more_hid = parseFloat(document.forms.roi_calc.isdn30_yc_more_hid.value);
		
		isdn30_bt_qtrly = nISDN30 * isdn30_bt_hid;
		isdn30_yc_qrtly = nISDN30 * (nISDN30 < 100 ? isdn30_yc_100_hid  : (nISDN30 < 1000 ? isdn30_yc_1000_hid  : isdn30_yc_more_hid ));
		isdn30_ann_sav = (isdn30_bt_qtrly - isdn30_yc_qrtly) * 4;

		total_saving = analog_ann_sav + isdn30_ann_sav;

		// Put the new values into the form fields
		document.forms.roi_calc.analog_bt_qtrly.value = floatToSterling(analog_bt_qtrly);
		document.forms.roi_calc.analog_yc_qtrly.value = floatToSterling(analog_yc_qrtly);
		document.forms.roi_calc.analog_annual_saving.value = floatToSterling(analog_ann_sav);

		document.forms.roi_calc.isdn30_bt_qtrly.value = floatToSterling(isdn30_bt_qtrly);
		document.forms.roi_calc.isdn30_yc_qtrly.value = floatToSterling(isdn30_yc_qrtly);
		document.forms.roi_calc.isdn30_annual_saving.value = floatToSterling(isdn30_ann_sav);

		document.forms.roi_calc.total_annual_saving.value = floatToSterling(total_saving);
		document.forms.roi_calc.calc_display.value = 'Your annual saving = ' + floatToSterling(total_saving);
	}

	function floatToSterling(val){
	// Take a number and return it as a currency value in pounds sterling
		var ret_str, dec_point, first_part, second_part;

		val = "" + Math.round(100 * val);
		// add leading spaces as needed
		while(val.length <= 2){
			val = "0" + val
		}

		// Insert decimal place
		dec_point = val.length - 2;
		first_part = val.substring(0, dec_point);
		second_part = val.substring(dec_point, val.length);
	
		ret_str = "." + second_part;
		// Add commas to seperate thousands
		for(var i = first_part.length, n = 0; i>=0; i--, n++){
			ret_str = first_part.charAt(i) + ret_str;
			if(n > 2 && i>0){
				ret_str = "," + ret_str;
				n = 0;
			}
		}

		//wtl_Tag5_151548();
		//return("£"+ret_str);
		return (unescape('%A3') + ret_str);
	}