function displayVal(n) {

		var x = Math.round(n * 10.0);

		return x / 10.0;

	}



	function isNumeric(sText) {

		//Determine whether a string is numeric

		

	   var ValidChars = "0123456789.";

   	var IsNumber=true;

   	var Char;

	

 		if(sText.length == 0) {

 			return false;

 		}

 		

   	for (i = 0; i < sText.length && IsNumber == true; i++) 

   	   { 

   	   Char = sText.charAt(i); 

   	   if (ValidChars.indexOf(Char) == -1) 

   	      {

   	      IsNumber = false;

   	      }

   	   }

   	return IsNumber;

   

   }

	



	function typeVisible() {

		var calcType;

		var e;

		

		with(document.pondCalculator) {

			//Determine type of pond requested

			if(pondType[0].checked) {

				calcType = "Rectangular";

			} else {

				calcType = "Oval";

			}

			//Retrieve span element for radius

			

			e = document.getElementById('radius');

			

			//Set visibility according to type of pond

			if(calcType == "Oval") {

				e.style.visibility = "visible";

			} else {

				e.style.visibility = "hidden";

			}

		}

	}

	

	function calculatePond() {

		//Perform the pond calculations

		

		var calcType = '';

		var nLength = 0.0;

		var nWidth = 0.0;

		var nAvgDepth = 0.0;

		var nMaxDepth = 0.0;

		var nRadius = 0.0;

		var nVolumeUS = 0.0;

		var nVolumeUK = 0.0;

		var nArea = 0.0;

		var nLinerWidth = 0.0;

		var nLinerLength = 0.0;

		var nUSPumpSize = 0.0;

		var nUKPumpSize = 0.0;

		var nTurnover = 0.0;

		var nMarginalStock = 0.0;

		var nIdealStock = 0.0;

		

		with(document.pondCalculator) {

			//Determine type of pond requested

			if(pondType[0].checked) {

				calcType = "Rectangular";

			} else {

				calcType = "Oval";

			}



			if(isNumeric(pondLength.value) == false) {

				alert("Please enter numeric value.");

				pondLength.focus();

				return;

			}

			if(isNumeric(pondWidth.value) == false) {

				alert("Please enter numeric value.");

				pondWidth.focus();

				return;

			}

			if(calcType == 'Oval' && isNumeric(pondRadius.value) == false) {

				alert("Please enter numeric value.");

				pondRadius.focus();

				return;

			}

			if(isNumeric(pondMaxDepth.value) == false) {

				alert("Please enter numeric value.");

				pondMaxDepth.focus();

				return;

			}

			if(isNumeric(pondAvgDepth.value) == false) {

				alert("Please enter numeric value.");

				pondAvgDepth.focus();

				return;

			}

			if(isNumeric(turnover.value) == false) {

				turnover.value = "1.5";

			}

			

			//Retrieve the values

			nWidth = parseFloat(pondWidth.value);

			nLength = parseFloat(pondLength.value);

			nMaxDepth = parseFloat(pondMaxDepth.value);

			nAvgDepth = parseFloat(pondAvgDepth.value);

			if(calcType == 'Oval') {

				nRadius = parseFloat(pondRadius.value);

			}

			nTurnover = parseFloat(turnover.value);

			

			nArea = (nWidth * nLength) + (nRadius * nRadius * Math.PI);

			surfaceArea.value = displayVal(nArea);

			nVolumeUK = nArea * nAvgDepth * 6.23;

			nVolumeUS = nVolumeUK * 1.201;

			ukVolume.value = displayVal(nVolumeUK);

			usVolume.value = displayVal(nVolumeUS);

			

			//Liner size

			nLinerLength = (nLength + nRadius) + (2 * nMaxDepth + 4);

			nLinerWidth = (nWidth + nRadius) + (2 * nMaxDepth + 4);

			linerHeight.value = displayVal(nLinerLength);

			linerWidth.value = displayVal(nLinerWidth);

			

			//Pump size

			nUSPumpSize = (nVolumeUS / nTurnover);

			nUKPumpSize = (nVolumeUK / nTurnover);

			usPump.value = displayVal(nUSPumpSize);

			ukPump.value = displayVal(nUKPumpSize);

			

			//Stock size

			nIdealStock = Math.sqrt(((nVolumeUS / 20.0) * 231.0) / 2.0);

			nMarginalStock = Math.sqrt(((nVolumeUK / 10.0) * 231.0) / 2.0);

			idealStock.value = Math.round(nIdealStock);

			marginalStock.value = Math.round(nMarginalStock);

		}

	}

//Aquarium Calculations	



function gallons(f) {

    f.USgallons.value = f.Length.value * f.Width.value * f.Height.value / 2.31;

    f.USgallons.value = Math.round(f.USgallons.value) / 100.0;

    f.UKgallons.value = f.Length.value * f.Width.value * f.Height.value / 2.7742;

    f.UKgallons.value = Math.round(f.UKgallons.value) / 100.0;

    

    f.Length1.value = f.Length.value * 254;

    f.Length1.value = Math.round(f.Length1.value) / 100;

    f.Width1.value = f.Width.value * 254;

    f.Width1.value = Math.round(f.Width1.value) / 100;

    f.Height1.value = f.Height.value * 254;

    f.Height1.value = Math.round(f.Height1.value) / 100;

    f.Liters.value = f.Length1.value * f.Width1.value * f.Height1.value / 10;

    f.Liters.value = Math.round(f.Liters.value) / 100;

}

function liter_volume(f) {

    f.Length.value = f.Length1.value / .0254;

    f.Length.value = Math.round(f.Length.value) / 100;

    f.Width.value = f.Width1.value / .0254;

    f.Width.value = Math.round(f.Width.value) / 100;

    f.Height.value = f.Height1.value / .0254;

    f.Height.value = Math.round(f.Height.value) / 100;

    f.Liters.value = f.Length1.value * f.Width1.value * f.Height1.value / 10;

    f.Liters.value = Math.round(f.Liters.value) / 100;

    f.USgallons.value = f.Length.value * f.Width.value * f.Height.value / 2.31;

    f.USgallons.value = Math.round(f.USgallons.value) / 100.0;

    f.UKgallons.value = f.Length.value * f.Width.value * f.Height.value / 2.7742;

    f.UKgallons.value = Math.round(f.UKgallons.value) / 100.0;

}    

function circular_gallons(f) {

    f.USgallons.value = (f.Diameter.value/2)* (f.Diameter.value/2) * Math.PI * f.Height.value / 2.31;

    f.USgallons.value = Math.round(f.USgallons.value) / 100;

    f.UKgallons.value = f.USgallons.value * 83.3;

    f.UKgallons.value = Math.round(f.UKgallons.value) / 100;



    f.Diameter1.value = f.Diameter.value * 254.0;

    f.Height1.value = f.Height.value * 254.0;

    f.Liters.value = (f.Diameter1.value/2) * (f.Diameter1.value/2) * Math.PI * f.Height1.value / 10000000;

    f.Liters.value = Math.round(f.Liters.value) / 100;

    

    f.Diameter1.value = Math.round(f.Diameter1.value) / 100;

    f.Height1.value = Math.round(f.Height1.value) / 100;

}

function circular_liters(f) {

    f.Liters.value = (f.Diameter1.value/2) * (f.Diameter1.value/2) * Math.PI * f.Height1.value / 10;

    f.Liters.value = Math.round(f.Liters.value) / 100;

    

    f.Diameter.value = f.Diameter1.value / .0254;

    f.Height.value = f.Height1.value / .0254;



    f.USgallons.value = (f.Diameter.value/2) * (f.Diameter.value/2) * Math.PI * f.Height.value / 2310000;

    f.USgallons.value = Math.round(f.USgallons.value) / 100.0;

    f.UKgallons.value = (f.Diameter.value/2) * (f.Diameter.value/2) * Math.PI * f.Height.value / 2774200;

    f.UKgallons.value = Math.round(f.UKgallons.value) / 100.0;

    

    f.Diameter.value = Math.round(f.Diameter.value) / 100;

    f.Height.value = Math.round(f.Height.value) / 100;



}    

function hex_gallons(f) {

    f.USgallons.value = (f.Width.value)* (f.Width.value/2) * (f.NumSides.value) * f.Height.value / 2.31;

    f.UKgallons.value = f.USgallons.value * .833;

    f.USgallons.value = Math.round(f.USgallons.value) / 100;

    f.UKgallons.value = Math.round(f.UKgallons.value) / 100;



    f.Width1.value = f.Width.value * 254.0;

    f.Height1.value = f.Height.value * 254.0;

    f.NumSides1.value = f.NumSides.value;

    f.Liters.value = (f.Width1.value) * (f.Width1.value/2) * f.NumSides1.value * f.Height1.value / 10000000;

    f.Liters.value = Math.round(f.Liters.value) / 100;

    

    f.Width1.value = Math.round(f.Width1.value) / 100;

    f.Height1.value = Math.round(f.Height1.value) / 100;

}

function hex_liters(f) {

    f.Liters.value = (f.Width1.value) * (f.Width1.value/2) * f.NumSides1.value * f.Height1.value / 10;

    f.Liters.value = Math.round(f.Liters.value) / 100;

    

    f.Width.value = f.Width1.value / .0254;

    f.Height.value = f.Height1.value / .0254;

    f.NumSides1.value = f.NumSides.value;



    f.USgallons.value = (f.Width.value) * (f.Width.value/2) * f.NumSides.value * f.Height.value / 2310000;

    f.USgallons.value = Math.round(f.USgallons.value) / 100.0;

    f.UKgallons.value = (f.Width.value) * (f.Width.value/2) * f.NumSides.value * f.Height.value / 2774200;

    f.UKgallons.value = Math.round(f.UKgallons.value) / 100.0;

    

    f.Width.value = Math.round(f.Width.value) / 100;

    f.Height.value = Math.round(f.Height.value) / 100;

}





function round(value) {

    value = Math.round(value * 100) / 100;

    return value;

}