What does the ^ (caret) symbol do in JavaScript?

Question

I have some JavaScript code:

<script type="text/javascript">
$(document).ready(function(){
  $('#calcular').click(function() {
    var altura2 = ((($('#ddl_altura').attr("value"))/100)^2);
    var peso = $('#ddl_peso').attr("value");
    var resultado = Math.round(parseFloat(peso / altura2)*100)/100;
    if (resultado > 0) {
      $('#resultado').html(resultado);
      $('#imc').show();
    };
  });
});
</script>

What does the ^ (caret) symbol mean in JavaScript?

score 96 · Accepted Answer · answered Sep 01 '10 at 13:12

96

The ^ operator is the bitwise XOR operator. To square a value, use Math.pow:

var altura2 = Math.pow($('#ddl_altura').attr("value")/100, 2);

answered Sep 01 '10 at 13:12

Gumbo

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6

in a language like Javascript where types are so loose they barely exist, i'm almost surprised there are even bitwise operations :) – tenfour Sep 01 '10 at 13:15
1

I know the pow function (the Loreal Web Master seems no...) but I couldn´t find the ^ operator for javascript. Thanks for the link! – Torres Sep 01 '10 at 13:22
3

Nice catch! Forwarded it to my spanish friend, who got a little shocked. Noticed how for example 200cm/70kg gives you a BMI of infinity ;-) – Michael Sep 01 '10 at 14:29
Haha, that´s the same test I did!! now I know the answer, I feel better. I was scared for having a BMI of infinity... – Torres Sep 01 '10 at 16:16
5

To square a value, multiply it by itself. It's faster and more accurate on almost all platforms. – Stephen Canon Sep 01 '10 at 18:57
8

Gets much easier in ES7 : `2**5 //32` – Vinay Nov 09 '16 at 05:22

score 49 · Answer 2 · answered Sep 01 '10 at 14:02

49

^ is performing exclusive OR (XOR), for instance

6 is 110 in binary, 3 is 011 in binary, and

6 ^ 3, meaning 110 XOR 011 gives 101 (5).

  110   since 0 ^ 0 => 0
  011         0 ^ 1 => 1
  ---         1 ^ 0 => 1
  101         1 ^ 1 => 0

Math.pow(x,2) calculates x² but for square you better use x*x as Math.pow uses logarithms and you get more approximations errors. ( x² ~ exp(2.log(x)) )

answered Sep 01 '10 at 14:02

Déjà vu

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Wasn't aware of the logarithm fact! Thanks! (It's thus probably also faster, isn't it?) – Michael Sep 01 '10 at 14:34
Likely to be faster (while math processors are pretty fast for `double` simple operations - log is likely to be slower, while using an optimization of the Taylor series). – Déjà vu Sep 01 '10 at 16:21
Wonder why Math.pow doesn't just use x*x ?! – Jowen Apr 22 '14 at 12:02
2

@Jowen for x² ... But what if you need to calculate x^2.123123? – Déjà vu Mar 20 '15 at 00:58

score 5 · Answer 3 · answered Sep 01 '10 at 13:12

5

This is the bitwise XOR operator.

answered Sep 01 '10 at 13:12

Petar Minchev

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score 3 · Answer 4 · answered Jul 19 '17 at 07:27

3

Its called bitwise XOR. Let me explain it:

You have :

Decimal Binary   
0         0
1         01
2         10
3         11

Now we want 3^2= ? then we have 11^10=?

11
10
---
01
---

so 11^10=01 01 in Decimal is 1.

So we can say that 3^2=1;

answered Jul 19 '17 at 07:27

Shubham Verma

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score 1 · Answer 5 · answered Sep 01 '10 at 13:13

The bitwise XOR operator is indicated by a caret ( ^ ) and, of course, works directly on the binary form of numbers. Bitwise XOR is different from bitwise OR in that it returns 1 only when exactly one bit has a value of 1.

Source: http://www.java-samples.com/showtutorial.php?tutorialid=820

What does the ^ (caret) symbol do in JavaScript?

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