var test,
   arr = ["item1", "item2", "item3", "item4", "item5"]; 
 
while(arr.length) {
    test = arr.pop();
}

var test, length,
    arr = ["item1", "item2", "item3", "item4", "item5"];
  
length = arr.length;
while(length) {
    test = arr[length--];
}