Binding

function display(){
 console.log(this); // 'this' will point to the global object
}
display(); 

var obj = {
 name: 'Saurabh',
 display: function(){
   console.log(this.name); // 'this' points to obj
  }
};
obj.display(); // Saurabh

var name = "uh oh! global";
var outerDisplay = obj.display;
outerDisplay(); // uh oh! global

function setTimeout(callback, delay){
   callback(); // callback = obj.display;
}
setTimeout( obj.display, 1000 );

var name = "uh oh! global";
setTimeout( obj.display, 1000 );
// uh oh! global

var name = "uh oh! global";
obj.display = obj.display.bind(obj); 
var outerDisplay = obj.display;
outerDisplay();
// Saurabh