weird-object-this-bind-example.js

var x = 5,
    o = {
        x: 10,
        doIt: function() {
            var x = 20;
            console.log(this.x);
            setTimeout(function(){
                console.log(this);
            }, 1000);
        }
    };
o.doIt();

// in the setTimeout this.x is undefined because this in that context of the setTimeout callback is the timeout object 
// if you bind o to the end of that function you then have access to the o object which contains x and the doIt function