var test = function(){
  console.log(this===window);
}
test.apply(null);//true
test.call(undefined);//true

var foo = {
  name:"mingming",
  logName:function(){
    console.log(this.name);
  }
}
var bar={
  name:"xiaowang"
};
foo.logName.call(bar);//xiaowang

function Animal(name){   
  this.name = name;   
  this.showName = function(){   
    console.log(this.name);   
  }   
}   

function Cat(name){  
  Animal.call(this, name);  
}   

var cat = new Cat("Black Cat");   
cat.showName(); //Black Cat

window.id="window";
document.querySelector('#test').onclick = function(){
  console.log(this.id);//test
  var fun = function(){
    console.log(this.id);
  }
  fun();//window
}

window.id="window";
document.querySelector('#test').onclick = function(){
  console.log(this.id);//test
  var fun = function(){
    console.log(this.id);
  }
  fun.call(this);//test
}

window.id="window";
document.querySelector('#test').onclick = function(){
  var that = this;
  console.log(this.id);//test
  var fun = function(){
    console.log(that.id);
  }
  fun();//test
}

function func(){
  "use strict"
  alert ( this );  // 输出：undefined
}
func();

(function(){
  Array.prototype.push.call(arguments,4);
  console.log(arguments);//[1, 2, 3, 4]
})(1,2,3)

var arr1=new Array("1","2","3"); 
var arr2=new Array("4","5","6"); 
Array.prototype.push.apply(arr1,arr2); 
console.log(arr1);//["1", "2", "3", "4", "5", "6"]

(function(){
  var maxNum = Math.max.apply(null,arguments);
  console.log(maxNum);//56
})(34,2,56);

console.log(Object.prototype.toString.call(123)) //[object Number]
console.log(Object.prototype.toString.call('123')) //[object String]
console.log(Object.prototype.toString.call(undefined)) //[object Undefined]
console.log(Object.prototype.toString.call(true)) //[object Boolean]
console.log(Object.prototype.toString.call({})) //[object Object]
console.log(Object.prototype.toString.call([])) //[object Array]
console.log(Object.prototype.toString.call(function(){})) //[object Function]