Question: I am debugging a website using firebug. The website opens a window, performs some operations and than closes it. This causes me to lose all of the firebug net history. Is there any way to prevent javastript from closing the window after its done, except changing the code?

Answer: 
I haven't tried to use it, but there's a settings in FF which supposedly lets you do what you wish.

Type about:config in the url bar and press enter. After a warning you'll see the list of config options. Search for dom.allow\_scripts\_to\_close\_windows and set its value to false.
You can rewrite the `open` method, which adds a `beforeunload` event. Have a look at the annotated code + bookmarklet below:

Code:

```
javascript:(function(w){
    var o = w.open;       /* Stores original `window.open` method */
    w.open = function() { /* Catches all window.open calls*/
        var x = o.apply(w, arguments); /* Calls original window.open */
        /* Bind beforeunload event */
        x.addEventListener('beforeunload',function(e){e.preventDefault()},true);
        return x;
    }
})(window);

```

Bookmarklet:

```
javascript:(function(w){var o=w.open;w.open=function(){var x=o.apply(w,arguments);x.addEventListener('beforeunload',function(e){e.preventDefault()},true);return x;}})(window);

```