javascript - Binded click loses context of my Class. JS -

I have a problem that I understand, but there is no way, how will it be known.

I have a simplified class:

  function drawing tab (canvas_id) {this.canvas_id = canvas_id; Bind_events () function bind_events () (click) (function (e) {var canvas = get_canvas () // works do_something_in_the_instance_who_called_click ()} function get_canvas () {return document.getElementById (canvas_id)} function do_something_in_the_instance_who_called_click () {Warning (this.canvas_id) // fail!}}  

Because when it clicks (which is not it ) inside, example But I need to change any one of them .. Is there any way, which can be many examples?

I do not really know how but get_canvas () work I'm using jQuery but probably not relevant to

This happens because you are calling the function without any object reference , but you can store this value:

  function DrawingTable (canvas_id) {var instance = this; // & lt; - `` Store this `value this.canvas_id = canvas_id; Click Bind_events () function bind_events () {$ (get_canvas ()) (function (e) {// Note that here `` this `value` will point to canvas gates,` example 'should also be used canvas = Get_canvas (); do_something_in_the_instance_who_called_click ();} function get_canvas () {return document.getElementById (canvas_id)} function do_something_in_the_instance_who_called_click () {alert (instance.canvas_id); // & lt; - use `this` value stored} }  

When you call a function, the this value is contained, for example:

  obj.method ( );  

If you have any , then will denote value obj , such as:

  MyFunction ();  

this inside myfunction will point to the global object.