Function.prototype.call or apply

1. 简介与语法

[color=red][size=large]apply[/size][/color]

[b]1. 语法[/b]
fun.apply(thisArg[, argsArray])

[b]2. 参数[/b]
[color=green]thisArg[/color]
The value of this provided for the call to fun. Note that this may not be the actual value seen by the method: if the method is a function in non-strict mode code, null and undefined will be replaced with the global object, and primitive values will be boxed.
[color=green]argsArray[/color]
An array like object, specifying the arguments with which fun should be called, or null or undefined if no arguments should be provided to the function.

[b]3. 简介[/b]
Calls a function with a given this value and arguments provided as an array (or an array like object).

NOTE: While the syntax of this function is almost identical to that of call(), the fundamental difference is that call() accepts an argument list, while apply() accepts a single array of arguments.

[color=red][size=large]call[/size][/color]

与apply类似,只是第第二个参数不一样
fun.call(thisArg[, arg1[, arg2[, ...]]])

[align=center][size=large][color=red]2.demo[/color][/size][/align]

[color=green][size=large]2.1 构造方法[/size][/color]

function Product(name, price) {
  this.name = name;
  this.price = price;
}

function Food(name, price) {
  Product.call(this, name, price);
  this.category = 'food';
}
// 用于instanceof的时候判断是true
//Food.prototype = new Product();

function Toy(name, price) {
  Product.apply(this, arguments);
  this.category = 'toy';
}
Toy.prototype = new Product();

var cheese = new Food('feta', 5);
var fun = new Toy('robot', 40);

如下图:

[img]http://dl.iteye.com/upload/attachment/0083/6324/ed313e49-41f9-36d9-88a2-267887a2504b.jpg[/img]

[color=green][size=large]2.2 匿名函数[/size][/color]

var animals = [
  {species: 'Lion', name: 'King'},
  {species: 'Whale', name: 'Fail'}
];

for (var i = 0; i < animals.length; i++) {
  (function (i) { 
    this.print = function () { 
      console.log('#' + i  + ' ' + this.species + ': ' + this.name); 
    } 
    this.print();
  }).call(animals[i], i);
}

2.3 调用自身

/* min/max number in an array */
var numbers = [5, 6, 2, 3, 7];

/* using Math.min/Math.max apply */
var max = Math.max.apply(null, numbers); /* This about equal to Math.max(numbers[0], ...) or Math.max(5, 6, ..) */
var min = Math.min.apply(null, numbers);