call,apply和bind之間的共同點(diǎn)是都可以改變this指向

語法如下：

```

var?obj?=?{

????????????name:'zhangsan',

????????????say:function(str,str2){

????????????????console.log(this.name+'?'+str+'?'+str2)??//?this??{name:'李四'}

????????????}

????????}

//?obj.say('hello')

????????//?obj.say.call({name:'李四'},'hello','world');//?obj.say?函數(shù)中的?this?變成了{(lán)name:'李四'}

????????//?obj.say.apply({name:'李四'},['hello','world'])

????????//obj.say.bind({name:'李四'},'hello','world');

???????var?f?=??obj.say.bind({name:'李四'},'hello','world');

???????f();

```

但是他們也有不同點(diǎn)：

1.apply的第二個(gè)參數(shù)是一個(gè)數(shù)組?

2.bind需要二次調(diào)用