I. Events
Recently, the project management fee was written in JS on the client. A major problem was found, such as 0.7*8.1 = 5.6699999999, 10.3-9.2 = 100000000014. Why are these problems? Is it a bug in JS's floating point operations? What should I do?
2. Response
"Baidu cannot be asked in case of internal affairs, but Google cannot be asked in case of foreign affairs" ah, I searched for information online, confirmed my thoughts, and found a solution. At the same time, I have my own solutions.
1. The online solution is to overwrite the floating point operations,CodeAs follows: (reproduced)
Code
// Division function, used to obtain accurate division results
// Note: There will be an error in the division result of JavaScript, which will be obvious when two floating point numbers are separated. This function returns a more precise division result.
// Call: accdiv (arg1, arg2)
// Returned value: the exact result of dividing arg1 by arg2
Function Accdiv (arg1, arg2 ){
VaR T1 = 0 , T2 = 0 , R1, R2;
Try {T1 = Arg1.tostring (). Split ( " . " )[ 1 ]. Length} Catch (E ){}
Try {T2 = Arg2.tostring (). Split ( " . " )[ 1 ]. Length} Catch (E ){}
With (Math ){
R1 = Number (arg1.tostring (). Replace ( " . " , "" ));
R2 = Number (arg2.tostring (). Replace ( " . " , "" ));
Return (R1 / R2) * POW (10, t2-t1 );
}
}
// Add a div Method to the number type to facilitate calling.
Number. Prototype. Div = Function (ARG ){
Return Accdiv ( This , ARG );
};
// Multiplication function, used to obtain accurate multiplication results
// Note: There is an error in the Javascript multiplication result, which is obvious when two floating point numbers are multiplied. This function returns a more accurate multiplication result.
// Call: accmul (arg1, arg2)
// Returned value: exact result of multiplying arg1 by arg2
Function Accmul (arg1, arg2)
{
VaR M = 0 , S1 = Arg1.tostring (), S2 = Arg2.tostring ();
Try {M + = S1.split ( " . " )[ 1 ]. Length} Catch (E ){}
Try {M + = S2.split ( " . " )[ 1 ]. Length} Catch (E ){}
Return Number (s1.replace ( " . " , "" )) * Number (s2.replace ( " . " , "" )) / Math. Pow (10, M );
}
// Add a mul Method to the number type to facilitate calling.
Number. Prototype. Mul = Function (ARG ){
Return Accmul (ARG, This );
};
// The addition function is used to obtain accurate addition results.
// Note: The addition result of JavaScript has an error, which is obvious when two floating point numbers are added. This function returns a more accurate addition result.
// Call: accadd (arg1, arg2)
// Returned value: Exact Results of adding arg2 to arg1
Function Accadd (arg1, arg2 ){
VaR R1, R2, M;
Try {R1 = Arg1.tostring (). Split ( " . " )[ 1 ]. Length} Catch (E) {r1 = 0 }
Try {R2 = Arg2.tostring (). Split ( " . " )[ 1 ]. Length} Catch (E) {r2 = 0 }
M = Math. Pow ( 10 , Math. Max (R1, R2 ));
Return (Arg1 * M + Arg2 * M) / M;
}
// Add an add method to the number type to facilitate calling.
Number. Prototype. Add = Function (ARG ){
Return Accadd (ARG, This );
}
// Subtraction Functions
Function Accsub (arg1, arg2 ){
VaR R1, R2, M, N;
Try {R1 = Arg1.tostring (). Split ( " . " )[ 1 ]. Length} Catch (E) {r1 = 0 }
Try {R2 = Arg2.tostring (). Split ( " . " )[ 1 ]. Length} Catch (E) {r2 = 0 }
M = Math. Pow ( 10 , Math. Max (R1, R2 ));
// Last modify by deeka
// Dynamic control precision length
N = (R1 > = R2) ? R1: R2;
Return (Arg2 * M - Arg1 * M) / M). tofixed (N );
}
// /Add a sub method to the number class to facilitate calling.
Number. Prototype. sub = Function (ARG ){
Return Accsub (ARG, This );
}
In this way, if you want to calculate 0.7*8.1, you only need to call the Mul method (0.7). Mul (8.1) to get an accurate answer.
2. My Solutions
This is a good method. However, I want to convert the floating point type into an integer and then perform an operation. For example, 0.7*8.1, we can calculate (0.7*10) * (8.1*10)/100, and the result is 5.67, obviously. Through project practice, we can get accurate results.
Iii. Summary:
1. Do not use JavaScript for complex operations, especially floating point operations.
2. If you must perform a floating point number operation, convert the floating point number to an integer before performing the operation.
