Example of precise addition and subtraction in js

Calculate addition and subtraction exactly. For example, 0.1+0.2=0.3 or 0.1-0.2=-0.1

 
function addFn(dataOne,dataTwo){ 

var dataOneInt=dataOne.toString().split(".")[0]; 
var dataOneFloat=""; 
var dataTwoInt=dataTwo.toString().split(".")[0]; 
var dataTwoFloat=""; 
var lengthOne=0; 
var lengthTwo=0; 
var maxlength=0; 

if(dataOne.toString().split(".").length==2){ 
dataOneFloat=dataOne.toString().split(".")[1]; 
lengthOne=dataOneFloat.toString().length; 

} 
if(dataTwo.toString().split(".").length==2){ 
dataTwoFloat=dataTwo.toString().split(".")[1]; 
lengthTwo=dataTwoFloat.toString().length; 

} 

maxLength=Math.max(lengthOne,lengthTwo); 
for(var i=0;i<maxLength-lengthOne;i++){ 
dataOneFloat+="0"; 
} 
for(var i=0;i<maxLength-lengthTwo;i++){ 
dataTwoFloat+="0"; 
} 

 
var one=dataOneInt+""+dataOneFloat; 
var two=dataTwoInt+""+dataTwoFloat; 
//alert("dataOne:"+dataOne+" dataTwo:"+dataTwo +" one:"+one+" two:"+two); 

 
var result= (Number(one)+Number(two))/Math.pow(10,maxLength); 

return result; 

}