> 
> **Possible Duplicate:**  
> 
> [Is Chrome's JavaScript console lazy about evaluating arrays?](https://stackoverflow.com/questions/4057440/is-chromes-javascript-console-lazy-about-evaluating-arrays) 
> 
> 
> 

I write next js function:

```
function popFromArray(arr){
    console.info(arr);
    console.info(arr.pop());
    console.info(arr);
}

```

When I write next code in console I expected next output:

```
>>> popFromArray([12, 432, 52, 523]);
[12, 432, 52, 523]
523
[12, 432, 52]

```

But I found strange behaviour for me (chrome and firefox):

```
>>> q = [12, 432, 52, 523];

>>> popFromArray(q);
[12, 432, 52, 523]
523
[12, 432, 52, 523]

>>> popFromArray(q);
[12, 432, 52]
523
[12, 432, 52]

>>> popFromArray(q);
[12, 432]
52
[12, 432]

```

Is anybody can explain why it happens?