js numerical summation method of ensuring accuracy is not lost

/ * * 
* Summation value is not lost to ensure the accuracy 
* @param arg1 value. 1 
* @param arg2 value 2 
* Number The @Returns {} returns the result of summation value 
* / 
function accAdd (arg1, arg2) {    
 IF (arg1 === "" || arg1 == null ) { 
arg1 = 0 ; 
} 
IF (arg2 === "" || arg2 == null ) { 
arg2 = 0 ; 
} 
return (parseFloat (arg1) * 10000 + parseFloat (arg2) * 10000) / 10000; 
}