Empty Array [Js]

How do you want to empty an array in Javascript?
Previously, I used to

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

However this method has a big flaw in referencing.

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

According to [1], there are a number of alternative to empty an array. I prefer:

arr.length = 0; // arr = [], arrB = []