Check whether an array exists in an array of arrays?

I'm using JavaScript, and would like to check whether an array exists in an array of arrays.

Here is my code, along with the return values:

var myArr = [1,3];
var prizes = [[1,3],[1,4]];
prizes.indexOf(myArr);
-1

Why?

It's the same in jQuery:

$.inArray(myArr, prizes);
-1

Why is this returning -1 when the element is present in the array?