function calculate()
{
	var time = 0, hour, min, sec, distance,	multiplier, speed, flag = 0;

	var selectDist  = new Array(
	.000568182,		//1 yard
	.000621371192,		//1 meter
	.2500,			//1 lap
	1.000,			//1 mile
	.621371192,		//1 Km
	3.10685596, 		//5K
	6.21371192, 		//10K
	13.109375, 		//1/2 Marathon
	26.21875		//Marathon
	);

	var displayDist = new Array(
	.2500, 			//1 lap
	1.000, 			//1 mile
	3.10685596, 		//5K
	6.21371192, 		//10K
	13.109375, 		//1/2 Marathon
	26.21875		//Marathon
	);

	for(var j=0; j<5; j++)
	{
		if(isNaN(document.inputForm.elements[j].value))
		{
			flag = 1;
		}
	}

	if(flag == 1) alert("Please enter numbers only - no text!");

	for(var j=0; j<3; j++)
	{
		time += (Math.pow(60, 2-j)) *
			(document.inputForm.hms[j].value)
	}

	distance = selectDist[document.inputForm.distances.value];
	multiplier = document.inputForm.mult.value;
	speed = distance * multiplier / time;		//speed in miles/second

	for(var row=0; row<6; row++)		//you know speed in miles/sec
	{
		time = displayDist[row]/speed;	//find each time in seconds
		hour = Math.floor(time/3600);	//hours is integer division
		time %= 3600;			//seconds left over
		min = Math.floor(time/60);	//minutes is integer division
		time %= 60;			//remaining seconds
		sec = Math.round(time);		//seconds

		document.outputForm.elements[3 * row + 0].value = hour;
		document.outputForm.elements[3 * row + 1].value = min;
		document.outputForm.elements[3 * row + 2].value = sec;
	}

	document.outputForm.averageSpeed.value = ("Average speed = " +
		Math.round(10*speed*3600)/10 + " miles/hour, " +
		Math.round(speed*1609.344*60) + " meters/minute");
}

function erase()
{
	document.inputForm.elements[0].value = "1";
	for(var j=2; j<5; j++)
	{
		document.inputForm.elements[j].value = "";
	}

	for(var j=0; j<19; j++)
	{
		document.outputForm.elements[j].value = "";
	}
}