jQuery: how to access parent function "this" from inside anonymous function?

Question

...
$.fn.annotateEdit = function(image, note) {
    if (note) {
        this.note = note;
    } else {
        var newNote = new Object();
        newNote.id = "new";
        this.note = newNote;
    }
}
...
var mynote = this.note;

form.find(':radio').change(function() {
    var vacancy = $(this).attr('value');
    mynote.vacancy = vacancy;
});
...

Is it possible to access "this.note" from the change() handler without defining "mynote"?

Answer 1

I use a pattern like this so I can access anything in the enclosing scope:

var that = this;
...

form.find(':radio').change(function () {
    that.note.vacancy = $(this).attr('value');
});

I am a fan of this pattern because it makes the code a little more readable. In my opinion, it is clear what it being accessed is part of the enclosing scope (as long as the usage of that is consistent).

Answer 2

Use $.proxy to bind it to a function...

   // Returns a function-------v
form.find(':radio').change( $.proxy(function() {

    var vacancy = $(this).attr('value');
    mynote.vacancy = vacancy;

}, this) );
//   ^---- ...that has its "this" value set as this argument.

Answer 3

There is no dedicated language mechanism for it. The common pattern is to store the this in local (closure) variable (often named self or that) of the outer function:

var self = this;
var innerFunction = function() {
    self.x = 1;
};

Answer 4

Check this - http://api.jquery.com/bind/ and "Passing event data" You can do something like this :

form.find(':radio').bind("change", {
context : this
}, function(event){
    console.log(event.data.context);
    console.log(event.data.context.note);
});