Question

What is the best approach for passing the this parameter of the init function to the change event handler and why?

Option 1 (using that = this).

SomeObject.prototype.init = function () {
    var that = this;
    this.$element.change(function () {            
        //do some some things with that.
        that.
    });

};

Option 2 (using event.data).

SomeObject.prototype.init = function () {

    this.$element.change({object:this }, function (e) {            
        //do some some things with the event data.
        e.data.object.
    });

};

Or another (better) one?

Answer 1

Imho the first one is a bit nicer. A 3rd way (if you can use ECMA5) would be

SomeObject.prototype.init = function () {
   this.$element.change(function () {            
       //do some some things with this.
       this.
    }.bind(this));
};