Question

Consider the following code:

for (var i = 0; i < 3; i++) {    var num = i + 0.50;    var output = num + " " + Math.round(num) + " " + num.toFixed(0);    alert(output); } 

In Opera 9.63 I get:

0.5 1 0

1.5 2 2

2.5 3 2

In FF 3.03 I get:

0.5 1 1

1.5 2 2

2.5 3 3

In IE 7 I get:

0.5 1 0

1.5 2 2

2.5 3 3

Note the bolded results. Why are this inconsistencies present? Does this mean that toFixed(0) should be avoided? What’s the correct way to round a number to the nearest integer?

Answer 1

Edit: To answer your edit, use Math.round. You could also prototype the Number object to have it do your bidding if you prefer that syntax.

Number.prototype.round = function() {   return Math.round(this); } var num = 3.5; alert(num.round()) 

I’ve never used Number.toFixed() before (mostly because most JS libraries provide a toInt() method), but judging by your results I would say it would be more consistent to use the Math methods (round, floor, ceil) then toFixed if cross-browser consistency is what you are looking for.