Function to compute square of each array element in JavaScript

Took 1 minute and 53 seconds to code method that returns square of each element of the array in JavaScript. Here is the code snippet.

Code:

arr = [1, 2, 3, 4];

function square(arr) {

var arr2 = [];

for (var i = 0; i < arr.length; i++) {

arr2.push(arr[i] * arr[i]);

}

return arr2;

}

document.write(square(arr));

Result:

1,4,9,16