`this` in javascript, scoping, execution context

this.js

/* how to bind `this` for callbacks, good example here too: 
http://ejohn.org/apps/learn/#84 
*/

var uiThing = {  
  parseResponse : function(data){
    this.data = data;
    this.renderUI()
  },
  renderUI : function(){ /* more code */ }
};

// remember to bind your callbacks to the proper context
$.ajax({
  type: 'GET',
  url: 'http://api.com/your/endpoint', 
  complete: uiThing.parseResponse.bind( uiThing ) 
});


/* Without the bind, Fail:
 
  Uncaught TypeError: Object #<Object> has no method 'renderUI'.

  why?
  
  When your callback ran, `this` inside your callback referenced the global context, aka Window. 
*/