jquery “this” binding issue on event handler (equivalent of bindAsEventListener in prototype)

问题

In jquery an event hadler's binding is the event generating DOM element (this points to the dom element). In prototype to change the binding of an event handler one can use the bindAsEventListener function; How can I access both the instance and the DOM element from a event handler?
Similar to How can I bind an event handler to an instance in JQuery?

function Car(){
    this.km = 0;
    $("#sprint").click(this.drive); //setup event handler
}

// event handler
// in it I need to access both the clicked element
// and the binding object (instance of car)
Car.prototype.drive = function(){
    this.km += 10; // i'd like to access the binding (but jq changes it)
    this.css({ // also the element
        left: this.km 
    }); 
    // NOTE that is inside this function I want to access them not elsewhere
}

var car = new Car();

回答1:

Hmm, maybe you can use jQuery.proxy()?

http://api.jquery.com/jQuery.proxy/

回答2:

Just bind a variable to this and use that.

function Car(){
    this.km = 0;
    var that = this;
    $("#sprint").click(function(){
         that.drive(this);
    });
}


Car.prototype.drive = function(element){
    this.km += 10; // i'd like to access the binding (but jq changes it)
    this.css({ // also the element
        left: this.km 
    }); 
    alert(element.innerHTML);
    // NOTE that is inside this function I want to access them not elsewhere
}

The handler passes the element to the instance

回答3:

The value this would otherwise point to (that is, the element the handler is attached to) is also passed in the currentTarget property of the event object. So, if you use the binding function you talked about:

Car.prototype.drive = function(e) {
    // this will be your car object
    // e.currentTarget will be the element that you attached the click handler to
}

回答4:

ok here you are :

var car = {km:0};
$("#sprint").click(function(){
    car.km += 10;
    $(this).css({ left: car.km });
});

I have not tested it but should be straight forward or as for where you went wrong is on your "this" which is looking at the "sprint" element not the "car" object.

来源：https://stackoverflow.com/questions/2864378/jquery-this-binding-issue-on-event-handler-equivalent-of-bindaseventlistener

标签

javascript

jquery

events

binding

this