It was for him to add up .. but it did not happen, I added parsefloat because I was giving error that it was not a function ..
var x = 0;
x = parseFloat((x + 0.4)).toFixed(1); // 0.4
x = parseFloat((x + 0.4)).toFixed(1); // 0.8
alert(x); // 0.8
x = parseFloat((x + 0.4)).toFixed(1); // 1.2
alert(x); // 1.2
It should be like in the comments but .. what's the problem? Is ToFixed doing something wrong? It always returns 0.4
The problem is that you are concatenating strings, (returning from toFixed ) and not adding numbers:
var x = 0;
x = parseFloat((x + 0.4)).toFixed(1); // "0.4" <-saída verdadeira
x = parseFloat((x + 0.4)); // "0.40.4" que depois de parseFloat e toFixed vira "0.4" novamente
The first "sum" gives "0.40.4", and the parsefloat takes as far as it understands (the first "0.40").
One solution would be this:
var x = 0;
x = parseFloat((x + 0.4).toFixed(1) ); // 0.4
document.body.innerHTML += x + '<br>';
x = parseFloat((x + 0.4).toFixed(1) ); // 0.8
document.body.innerHTML += x + '<br>';
x = parseFloat((x + 0.4).toFixed(1) ); // 1.2
document.body.innerHTML += x + '<br>';Notes:
The "tofixed" in this case could be applied in another order, for example at the time of displaying on the screen only. I just kept the code so you could compare with the original.
I changed the alert to innerHTML just to make it easier to read here on the page.
Put simply:
var x = 0;
x += 0.4 // 0.4
document.body.innerHTML += x.toFixed(1) + '<br>';
x += 0.4 // 0.8
document.body.innerHTML += x.toFixed(1) + '<br>';
x += 0.4 // 1.2
document.body.innerHTML += x.toFixed(1) + '<br>';Here we simply parseFloat, since toFixed was used only when displaying on the screen, without disturbing the sums.
The problem is that these numbers are in string format and not number .
What these methods return:
Accepts a string and converts to number without rounding. The similar method that rounds integers is parseInt(string, base); . Returns in number format.
Accepts a number with decimals (fractional part). Returns a string .
I suggest creating a function that does this, and can handle different cases:
function soma(a, b, casasDecimais) {
if (typeof a == 'string') a = parseFloat(a);
if (typeof b == 'string') b = parseFloat(b);
var soma = a + b;
return soma.toFixed(casasDecimais);
}