Programming Forums > Web Development and Design > JavaScript and Client-Side Browser Scripting

MiKuS · Jun 5th, 2007, 11:01 PM

I currently am making a calculator (to learn javascript better)

it's a karvonen heart rate calculator which calculates what your target heart rate BPM should be for a percentage workout, the formula is as follows:

(maximum heart rate = maximum achievable heart rate)
(minimum heart rate = heart rate measured just after waking up)

maximum heart rate - minimum heart rate * workout percentage + minimum heart rate = target bpm

ok, now i can get the formula kinda working.. the poblem i have is with this code:

targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)*percentZoneMin/100)+minHeartRate;

instead of adding minHeartRate it joins it like two strings like 4499 instead of showing 143 (44+99). Below is the code i'm using

(Toggle Plain Text)

function calc(form){
var maxHeartRate;
var minHeartRate;
var percentZoneMin;
var percentZoneMax;
var targetHeartRateLow;
var targetHeartRateHigh;

minHeartRate=form.rest_hr.value;
maxHeartRate=form.max_hr.value;
percentZoneMin=form.percent_zone1.value;
percentZoneMax=form.percent_zone2.value;

targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)*percentZoneMin/100)+minHeartRate;
targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)*percentZoneMax/100)+minHeartRate;
form.target_hr1.value=targetHeartRateLow;
form.target_hr2.value=targetHeartRateHigh;

}

Infinite Recursion · Jun 6th, 2007, 8:09 AM

look into using the parseInt function.
(http://www.w3schools.com/jsref/jsref_parseInt.asp)

MiKuS · Jul 9th, 2007, 12:44 AM

it's been a while since i last posted (been busy) but i got it in the end, here is the code i used.

 javascript Syntax (Toggle Plain Text) 
//Work Out Heart Rate Min - Max
function calc(form){
var maxHeartRate;
var minHeartRate;
var percentZoneMin;
var percentZoneMax;
var targetHeartRateLow;
var targetHeartRateHigh;
//Get form values
minHeartRate=parseInt(form.rest_hr.value,10);
maxHeartRate=parseInt(form.max_hr.value,10);
percentZoneMin=form.percent_zone1.value;
percentZoneMax=form.percent_zone2.value;
//Run our calculation
targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)*percentZoneMin/100)+minHeartRate;
targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)*percentZoneMax/100)+minHeartRate;
//update our form
form.target_hr1.value=targetHeartRateLow;
form.target_hr2.value=targetHeartRateHigh;
 
}
//Work Out Heart Rate Min - Max
function calc(form){
var maxHeartRate;
var minHeartRate;
var percentZoneMin;
var percentZoneMax;
var targetHeartRateLow;
var targetHeartRateHigh;
//Get form values
minHeartRate=parseInt(form.rest_hr.value,10);
maxHeartRate=parseInt(form.max_hr.value,10);
percentZoneMin=form.percent_zone1.value;
percentZoneMax=form.percent_zone2.value;
//Run our calculation
targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)*percentZoneMin/100)+minHeartRate;
targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)*percentZoneMax/100)+minHeartRate;
//update our form
form.target_hr1.value=targetHeartRateLow;
form.target_hr2.value=targetHeartRateHigh;

}

Thanks for the help.

Grich · Sep 23rd, 2007, 6:46 PM

I know it's over, but you could also use the Number() function as well as the parseInt() function.

It brings back a float / double.

Jun 5th, 2007, 11:01 PM	#1
MiKuS Programmer Join Date: Jun 2007 Posts: 84 Rep Power: 1	Help with Calculator I currently am making a calculator (to learn javascript better) it's a karvonen heart rate calculator which calculates what your target heart rate BPM should be for a percentage workout, the formula is as follows: (maximum heart rate = maximum achievable heart rate) (minimum heart rate = heart rate measured just after waking up) maximum heart rate - minimum heart rate * workout percentage + minimum heart rate = target bpm ok, now i can get the formula kinda working.. the poblem i have is with this code: targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)percentZoneMin/100)+minHeartRate; instead of adding minHeartRate it joins it like two strings like 4499 instead of showing 143 (44+99). Below is the code i'm using (Toggle Plain Text) function calc(form){ var maxHeartRate; var minHeartRate; var percentZoneMin; var percentZoneMax; var targetHeartRateLow; var targetHeartRateHigh; minHeartRate=form.rest_hr.value; maxHeartRate=form.max_hr.value; percentZoneMin=form.percent_zone1.value; percentZoneMax=form.percent_zone2.value; targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)percentZoneMin/100)+minHeartRate; targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)percentZoneMax/100)+minHeartRate; form.target_hr1.value=targetHeartRateLow; form.target_hr2.value=targetHeartRateHigh; } function calc(form){ var maxHeartRate; var minHeartRate; var percentZoneMin; var percentZoneMax; var targetHeartRateLow; var targetHeartRateHigh; minHeartRate=form.rest_hr.value; maxHeartRate=form.max_hr.value; percentZoneMin=form.percent_zone1.value; percentZoneMax=form.percent_zone2.value; targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)percentZoneMin/100)+minHeartRate; targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)*percentZoneMax/100)+minHeartRate; form.target_hr1.value=targetHeartRateLow; form.target_hr2.value=targetHeartRateHigh; }

Jun 6th, 2007, 8:09 AM	#2
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,436 Rep Power: 7	look into using the parseInt function. (http://www.w3schools.com/jsref/jsref_parseInt.asp) __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Jul 9th, 2007, 12:44 AM	#3
MiKuS Programmer Join Date: Jun 2007 Posts: 84 Rep Power: 1	it's been a while since i last posted (been busy) but i got it in the end, here is the code i used. javascript Syntax (Toggle Plain Text) //Work Out Heart Rate Min - Max function calc(form){ var maxHeartRate; var minHeartRate; var percentZoneMin; var percentZoneMax; var targetHeartRateLow; var targetHeartRateHigh; //Get form values minHeartRate=parseInt(form.rest_hr.value,10); maxHeartRate=parseInt(form.max_hr.value,10); percentZoneMin=form.percent_zone1.value; percentZoneMax=form.percent_zone2.value; //Run our calculation targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)percentZoneMin/100)+minHeartRate; targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)percentZoneMax/100)+minHeartRate; //update our form form.target_hr1.value=targetHeartRateLow; form.target_hr2.value=targetHeartRateHigh; } //Work Out Heart Rate Min - Max function calc(form){ var maxHeartRate; var minHeartRate; var percentZoneMin; var percentZoneMax; var targetHeartRateLow; var targetHeartRateHigh; //Get form values minHeartRate=parseInt(form.rest_hr.value,10); maxHeartRate=parseInt(form.max_hr.value,10); percentZoneMin=form.percent_zone1.value; percentZoneMax=form.percent_zone2.value; //Run our calculation targetHeartRateLow=Math.floor((maxHeartRate-minHeartRate)percentZoneMin/100)+minHeartRate; targetHeartRateHigh=Math.floor((maxHeartRate-minHeartRate)percentZoneMax/100)+minHeartRate; //update our form form.target_hr1.value=targetHeartRateLow; form.target_hr2.value=targetHeartRateHigh; } Thanks for the help. Last edited by MiKuS; Jul 9th, 2007 at 12:57 AM. Reason: turned on syntax highlighting

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Sep 23rd, 2007, 6:46 PM	#4
Grich Hobbyist Programmer Join Date: Sep 2007 Location: Sydney - Australia Posts: 137 Rep Power: 1	I know it's over, but you could also use the Number() function as well as the parseInt() function. It brings back a float / double.

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Programming Forums > Web Development and Design > JavaScript and Client-Side Browser Scripting

Help with Calculator