call apply bind 改版this指向
//var name ='jary'；
//var a ={
name:'Tom'，
say:function(){
console.log(this,name);
}
}
var f =a,say；
var obj={
name:'zhangsan',
say：function(str,str2){
conslole.log(this.name+ ' '+str+' ' +str2)
// obj.say.call({name:'宁宁'});
obj.say.call({name:'宁宁'},'hello','world');
obj.say.apply({name:'宁宁'},'hello','world');
var f = obj.bind({name:'宁宁'})
