Implementation of JavaScript shift() function

Took 13 minutes and 24 seconds to implement JavaScript shift() function. Here is the code snippet.

Function:

arr=['a', 'b', 'c'];

function shift(arr) {

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

arr[i] = arr[i+1];

}

arr.pop();

return arr;

}

shift(arr);

document.write(arr);

Result:

b,c