"How to attach or detach a handler function to an event, such as click, focus, or submit. Modern browsers support addEventListener() and removeEventListener() for adding or removing event handlers; IE 8 has its own methods."
"Have you ever tried to call removeEventListener on a previously attached element and couldn't remove it? Did you maybe try to pass a function to addEventListener that is bound to another context? The context of the callback that we are passing to addEventListener is the same as the event." read »