> Let's look at the method checkAll in Contact object:
>
> var Contact = {
> initialize: function(json,id_contact){
>
> $('check-all').observe('click',this.checkAll.bindAsEventListener(this));
> },
> checkAll: function(e) {
> e.stop();
> this.contactChecked = [];
>
> $$('#contacts-ul .contact-checkbox').each(function(c){
> c.checked = true;
> Contact.contactChecked.push(parseInt(c.value));
>
> Here 'this' is a window object so I could use bind(this) and then use
> this.contactChecked,
> but I can skip bind and use Contact.contactChecked which I often do.
The behaviour depends on whether you call the constructor with 'new'
or not (another of the features that Crockford describes as 'very
bad').
If you call it as 'new Contact', than inside the 'initialize', 'this'
refers to the new Contact object you are creating, and checkAll will
be bound so that inside it 'this' also refers to that Contact object.
If you call the constructor without 'new', then 'this' refers to the
global object, and that is what will be bound as 'this' inside
'checkAll'.
So yes, for this sort of use you usually do need 'bind'. You very
rarely need 'bindAsEventListener', and I cannot remember what the
special case is that it is designed for.
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