<!-- Begin of JavaScript code; this code is only for JavaScript-capable browsers
// Original script: Anton Steenkamp
// Website: http://www.sportsdigest.co.za
// This script may be copied and used without any changes or modifications.
// If you so wish to use this script on your site, feel free. I am only asking
// a linked reference to www.sportsdigest.co.za. If you let me know the website
// where you are using it, I'll create a link to yours as well.

function newWindow()
	{
	helpWindow = window.open('hlp_bin/hrhlp.htm','hlpWin','width=580,height=430')
	}

function KarvonenWindow()
	{
	KarvonenWindow = window.open('hlp_bin/karvonen.htm','karvonenWin','width=385,height=300')
	}


function hrcalc() {

	foundError = false;
		if(document.hrprediction.age.value == "")    {
		alert("\nPlease enter any reasonable age.");
		foundError = true;
		document.hrprediction.age.focus();
		return false;
		}
	
	foundError = false;
		if(document.hrprediction.rhr.value == "")    {
		alert("\nPlease enter your resting heart rate.");
		foundError = true;
		document.hrprediction.rhr.focus();
		return false;
		}
	
	// Codes
	// MHR - Maximum Heart Rate
	// MMHR - Maximum Heart Rate
	// RHR - Resting Heart Rate
	// HRR - Heart Rate Reserve
	
	// ACTUAL INFORMATION
	// Actual Age (AGE)
	AGE = document.hrprediction.age.value;

	// Measured Maximum Heart Rate (MMHR)
	MMHR = document.hrprediction.mmhr.value;
	
	// Actual Resting Heart Rate (RHR)
	RHR = document.hrprediction.rhr.value;

	// Predict MHR
	if(document.hrprediction.sex.value == "male")
		MHR = Math.round(205 - (0.5 * AGE));
	if(document.hrprediction.sex.value == "female")
		MHR = Math.round(211 - (0.5 * AGE));
	if(MMHR > "0")
		MHR = MMHR;
	
	document.hrprediction.mhr.value = MHR;
		
	if(MMHR == "")
		MMHR = MHR;
			
	document.hrprediction.mmhr.value = MMHR;
	
	// Predict Heart Rate Reserve (HRR)
	HRR = (MHR - RHR);

//	document.hrprediction.hrr.value = HRR;
	
	// CALCULATE VALUES FOR TABLE
	// Zone 1
	MIN1 = document.hrtable.min1.value;
	MAX1 = document.hrtable.max1.value;
	
	MINHR1 = Math.round((MIN1 / 100) * (HRR * 1) + (RHR * 1));
	MAXHR1 = Math.round((MAX1 / 100) * (HRR * 1) + (RHR * 1));
	
	document.hrtable.minhr1.value = MINHR1;
	document.hrtable.maxhr1.value = MAXHR1;
	
	// Zone 2
	MIN2 = document.hrtable.min2.value;
	MAX2 = document.hrtable.max2.value;
	
	MINHR2 = Math.round((MIN2 / 100) * (HRR * 1) + (RHR * 1));
	MAXHR2 = Math.round((MAX2 / 100) * (HRR * 1) + (RHR * 1));	

	document.hrtable.minhr2.value = MINHR2;
	document.hrtable.maxhr2.value = MAXHR2;

	// Zone 3
	MIN3 = document.hrtable.min3.value;
	MAX3 = document.hrtable.max3.value;
	
	MINHR3 = Math.round((MIN3 / 100) * (HRR * 1) + (RHR * 1));
	MAXHR3 = Math.round((MAX3 / 100) * (HRR * 1) + (RHR * 1));	
	
	document.hrtable.minhr3.value = MINHR3;
	document.hrtable.maxhr3.value = MAXHR3;

	// Zone 4
	MIN4 = document.hrtable.min4.value;
	MAX4 = document.hrtable.max4.value;
	
	MINHR4 = Math.round((MIN4 / 100) * (HRR * 1) + (RHR * 1));
	MAXHR4 = Math.round((MAX4 / 100) * (HRR * 1) + (RHR * 1));	
	
	document.hrtable.minhr4.value = MINHR4;
	document.hrtable.maxhr4.value = MAXHR4;

	// Zone 5
	MIN5 = document.hrtable.min5.value;
	MAX5 = document.hrtable.max5.value;
	
	MINHR5 = Math.round((MIN5 / 100) * (HRR * 1) + (RHR * 1));
	MAXHR5 = Math.round((MAX5 / 100) * (HRR * 1) + (RHR * 1));	
	
	document.hrtable.minhr5.value = MINHR5;
	document.hrtable.maxhr5.value = MAXHR5;
	
	}

function clearall()
	{
	document.hrprediction.age.value = "";
	document.hrprediction.mmhr.value = "";
	document.hrprediction.rhr.value = "55";
	document.hrprediction.mhr.value = "";
//		document.hrprediction.hrr.value = "";
	document.hrtable.min1.value = "50";
	document.hrtable.max1.value = "60";
	document.hrtable.min2.value = "60";
	document.hrtable.max2.value = "70";
	document.hrtable.min3.value = "70";
	document.hrtable.max3.value = "80";
	document.hrtable.min4.value = "80";
	document.hrtable.max4.value = "90";
	document.hrtable.min5.value = "90";
	document.hrtable.max5.value = "100";
	document.hrtable.minhr1.value = "";
	document.hrtable.maxhr1.value = "";
	document.hrtable.minhr2.value = "";
	document.hrtable.maxhr2.value = "";
	document.hrtable.minhr3.value = "";
	document.hrtable.maxhr3.value = "";
	document.hrtable.minhr4.value = "";
	document.hrtable.maxhr4.value = "";
	document.hrtable.minhr5.value = "";
	document.hrtable.maxhr5.value = "";
	document.hrprediction.age.focus();		
	}

// End of JavaScript code -->