(1) write a bind function, to make a function call other function with its parameters:
Function.prototype.bind = Function.prototype.bind || function(context){
  var self = this;

  return function(){
    return self.apply(context, arguments);
  };
}

function Foo(data1, data2) {
  this.x = data1;
  this.y = data2;
  console.log('Foo', this.x, this.y);
};

var bar = {};
var data1='123456', data2 = { a:'b', c:'d' };

Foo.bind(bar)(data1, data2); //same: bar = new Foo(data1, data2);
bar; //Object {x: "123456", y:{ a:'b', c:'d' }}


(2) what's wrong with the following function, and how to improve it?
  for(var i=0; i<3; i++) {
    setTimeout(function() {
	   console.log(i);
	}, 1000);
  }
  // wrong return: 3 3 3
  // improve:
  for(var i=0; i "David", "Accounts"
function Manager() {
    this.name_ary = [];
    Employee.apply(this, arguments);
}

Manager.prototype = Employee.prototype;
Manager.prototype.getDirectReports  = function() {
    return this.name_ary.join(', ');
}
Manager.prototype.setDirectReposts = function () {
   this.name_ary = Array.prototype.slice.call(arguments);
}

var david= new Manager( "David", "Accounts");
david.getInfo(); // Accounts David

david.setDirectReposts('Vijay', 'William');
console.log(david.getDirectReports()); // Vijay, William

(7) other solution:
function Manager() {
    this.name_ary = [];
	Employee.apply(this, arguments);
}

Manager.prototype = new Employee();
Manager.prototype.constructor=Manager;
Manager.prototype.getDirectReports  = function() {
    return this.name_ary.join(', ');
}
Manager.prototype.setDirectReposts = function () {
   this.name_ary = Array.prototype.slice.call(arguments);
}

var david= new Manager( "David", "Accounts");
david.getInfo(); // Accounts David

david.setDirectReposts('Vijay', 'William');
console.log(david.getDirectReports()); // Vijay, William



(8) sort a array of hash.
// Array of objects.  [{name:'vijay', id: '10'}, ....]

// Sort the array by name.
var arr =  [{name:'ben', id: '1'}, {name:'vijay', id: '10'}, {name:'bill', id: '1'}, {name:'william', id: 20}];
arr.sort(function(a,b) {
     if ( a.name  b.name )
       return 1;
     return 0;
 } );
console.log(arr); // sequence: ben,bill,vijay,william


(9) curry
var paths=['abc','efg','zzz','xxx'];
function simpleURL(protocol, domain, path) { return protocol + '://' + domain + '/' + path; }
var siteDomain='dixitruth.com'
paths.map(simpleURL.bind(null, 'http', siteDomain));
["http://dixitruth.com/abc", "http://dixitruth.com/efg", "http://dixitruth.com/zzz", "http://dixitruth.com/xxx"]

(10)
var one = {
  name: 'object',
  say: function(greet) {
    return greet + ', ' + this.name;
  }
};
var two = { name: 'another object' };
one.say.call(two, 'hello'); //"hello, another object"