//1. Write the following function
isTwoAParam(1,4) //false
isTwoAParam(5,3,1,2) //true

function isTwoAParam() {
    return [].slice.apply(arguments, [0]).indexOf(2) >=0;
}

function isTwoAParam() {
   var args = [].slice.call(arguments, 0);
   for(var i=0, len=args.length; i<len; i=i+1) {
       if(args[i] === 2) return true;
   }
   return false;
}

//2: 0..9
for(var i = 0; i < 10; i++) {
    (function(m) {
        setTimeout(function() {
          console.log(m);
        }, i)
    })(i)
}

//3. tricky here: after hoisting function a(), it becomes local variable:
var a=1;
var b = function() {
  a=10;
  return;
  function a() {}
}
b();
console.log(a);//1
//3. tricky here: after hoisting function a(), it becomes local variable:
var a=1;
var b = function() {
  var a = undefined;
  function a() {}
  a = 10; // now a is local variable, not global.
  return;
}
b();
console.log(a);