adding to [removed] event?

Question

I\'m wondering how to add another method call to the window.onload event once it has already been assigned a method call.

Suppose somewhere in the script I have this

Answer 1

There are basically two ways

1. store the previous value of window.onload so your code can call a previous handler if present before or after your code executes

2. using the addEventListener approach (that of course Microsoft doesn't like and requires you to use another different name).

The second method will give you a bit more safety if another script wants to use window.onload and does it without thinking to cooperation but the main assumption for Javascript is that all the scripts will cooperate like you are trying to do.

Note that a bad script that is not designed to work with other unknown scripts will be always able to break a page for example by messing with prototypes, by contaminating the global namespace or by damaging the dom.