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can't get the output from javascript

var weightkg=document.getElementById('weight').value;
var heightinm=document.getElementById('height').value;
function bmival (weightkg,heightinm){
var hout=heightinm*2
var output=weightkg/hout
//make a full number
// var r= Math.trunc(o)
if (output<=18.5){
return document.getElementById('print').innerHTML=`Your BMI is ${output} you are underweight` ;
}
else if(output>18.5 && o<25.5){
return document.getElementById('print').innerHTML=`Your BMI is ${output} You come under fit catogery`;
}
else{
return document.getElementById('print').innerHTML=`Your BMI is ${output} you are overweight and obese`;
}
}
[i am making a bmi cal that take input from user but i am getting a error and don't know what i am doing wrong]
**
this is js code and when i run i get a NaN instead of Number **

The values from an input field are strings so you must convert them into numbers
var heightinm = +document.getElementById('height').value; // one way to do it.

The value you get from
var weightkg=document.getElementById('weight').value;
seems to be a string instead of number. You need to convert values to do Math operations on them. NaN tells you output is not a number. Turn your values to number with parseInt method.
var weightkg = parseInt(document.getElementById('weight').value);
or you can just put a "+" to convert a string into number
var weightkg = +document.getElementById('weight').value;
For Example.
const input = document.getElementById('input');
const defaultStringInput = document.getElementById('input').value;
const inputConverted = parseInt(document.getElementById('input').value);
const inputConverted2 = +document.getElementById('input').value;
input.addEventListener('change', () => {
console.log(typeof defaultStringInput); // string
console.log(typeof inputConverted); // number
console.log(typeof inputConverted2); // number
});

getting NaN message in javascript while adding up multiple text fields

I am developing a simple application form where I am calculating experiences from maximum three employers. Now I want to add them up . The experiences are in the form of X years Y months and Z days. I have written following javascript function --
function total(){
var td;
var fd=parseInt(document.getElementById("LoS_days1").value);
var sd=parseInt(document.getElementById("LoS_days2").value);
var ld=parseInt(document.getElementById("LoS_days3").value);
var tm;
var fm=parseInt(document.getElementById("LoS_months1").value);
var sm=parseInt(document.getElementById("LoS_months2").value);
var lm=parseInt(document.getElementById("LoS_months3").value);
var ty;
var fy=parseInt(document.getElementById("LoS_year1").value);
var sy=parseInt(document.getElementById("LoS_year2").value);
var ly=parseInt(document.getElementById("LoS_year3").value);
td = (fd +sd +ld);
var rd = td%30;
var cm = Math.floor(td/30);
document.getElementById("Totalexp_day").value=rd;
tm = (cm + fm +sm +lm);
var rm = tm%12;
var cy = Math.floor(ty/12);
document.getElementById("Totalexp_month").value=rm;
ty = (cy + fy +sy +ly);
document.getElementById("Totalexp_year").value=ty;
}
I am getting a NaN message in each of the Totalexp_day, Totalexp_month and Totalexp_day field. Earlier I had some modified code that was not showing NaN message but it was not showing the desired results. Kindly suggest what to do to eliminate these two errors.

parseInt(document.getElementById("LoS_days1").value)
if the first character of the string cannot be converted to a number, parseInt will return NaN.
To avoid this, you can so something like is suggested here:
parseInt(document.getElementById("LoS_days1").value) || 0

If document.getElementById("Totalexp_day").value is empty then also it will return NaN. Make sure you have some number there.
Second alternative is reading document.getElementById("Totalexp_day").innerHTML and then applying parseInt
Probably you alert or console log the document.getElementById("Totalexp_day").value you would be more clearer why this problem is comming

get value of string before and after / in javascript

suppose i have 10 localstorage like blow:
localStorage.setItem("item01","this is a value/100");
localStorage.setItem("item02","this new is a value/110");
localStorage.setItem("item03","this is a good value/120");
localStorage.setItem("item04","this is a nice value/130");
I need a java script code to check if the key of for example item01 is not 0 then put the data of item01 before / to xyz and the data after / to rfv variable.

I would suppose you split the data-string along the character "/". Something like:
var lsData = localStorage.getItem("item01");
var dataArray = lsData.split("/");
if(dataArray.length === 2){
var xyz = dataArray[0];
var rfv = dataArray[1];
}
else{
... error-code (could not split exactly)...
}

This is an answer to your question "get value of string before and after / in javascript".
Like I stated in the comments you can split a string into an array of substrings using a delimiter.
jsfiddle
var str= "this is a value/100";
var temp=str.split("/");
var xyz = temp[0]; //->this is a value
var rfv = temp[1]; //->100
alert('xyz = '+xyz+'\nrfv = '+rfv);

this should do it...
I'm assuming you know how to get the localStorage value, so I'm just posting an example.
var a = "this is a value/100"
var b = /^(.*?)\/(\w+)/.exec(a);
var text = b[1]
var value = b[2]

Locating MAX Number in a string for a list of records

I am relatively new to JavaScript and trying to get the following achievement.
Lets say we have the following data records.
Example data records:
A_ID_R1_V1
A_ID_R1_V2
A_ID_R2_V1
Basically I am looking for two results:
1.Create a string based on record A_ID_R1_V2.
Input = A_ID_R1_V2
Output = A_ID_R1_V3
My thoughts about this is so locate the MAX V<#> for A_ID_R1_ and then add 1.
2.Create a string based on record A_ID_R2_V1.
Input = A_ID_R2_V1
Output = A_ID_R3_V1
My thoughts about this is so locate the MAX R<#> for all records and then add 1.
Thanks a lot in advance!!!!!!!!

I have strong feeling that this is some kind of school homework...
Anyhow, this will do the job, but its not sophisticated nor very effective
function updateId(letter){
var pos = (letter === 'V')?3:2;
var parts = id.split('_');
var num = parseInt(parts[pos].substring(1,parts[pos].length));
parts[pos] = letter+(num+1);
id = parts.join('_');
logVal(id);
}

try this with regex: http://jsfiddle.net/mig1098/wh6n2oqL/
newEntry = function(entry){
var str2 = entry.replace(/\d+$/,'');
var num = parseInt(entry.replace(/A_ID_R(\d+)_V/,''));
num = num+1;
return str2+num;
}

Having trouble converting user input into a graphic bar

The code seems to work fine when inputting numbers 1-9 but anything above doesn't work, what could be the issue? Here is the code:
var varkString = prompt('Enter your VARK scores - [visual|aural|read|kinesthetic]','9|3|11|10');
var subStrings = varkString.split('|');
var visual = varkString[0];
var aural = varkString[1];
var read = varkString[2];
var kinesthetic = varkString[3];
var varkBar = 30*visual
document.writeln('<img src="bar_blue.png" width='+varkBar+' height="25"/>');{
}
Edit: Solved

You are parsing first character when you are getting visual, second on aural and third on read.
I belive that you want to use subStrings
var visual = subStrings[0];
var aural = subStrings[1];
var read = subStrings[2];

when you are slpiting the string varkString the array will automatically constructed and assigned to subStrings.so use it like this:
var subStrings = varkString.split('|');
var visual = subStrings[0];
var aural = subStrings[1];
var read = subStrings[2];
var kinesthetic = subStrings[3];