Call(就像打電話，只能一個一個的打)
var obj = { num:2};
var addToThis = function(a){
return this.num+a;
};
console.log(addToThis.call(obj,3));// 5
// functionname.call(obj,functionarguments);
如果想傳入函數多個參數呢，如下
var obj = { num:2};
var addToThis = function(a,b,c){
return this.num+a+b+c;
};
console.log(addToThis.call(obj,1,2,3));
// functionname.call(obj,functionarguments);
Apply（它可以同時應用于一個數組）
var obj = { num:2};
var addToThis = function(a,b,c){
return this.num+a+b+c;
};
// console.log(addToThis.call(obj,1,2,3));
// functionname.call(obj,functionarguments);
var arr = [1,2,3];
console.log(addToThis.apply(obj,arr));
var obj = { num:2};
var obj2 = { num:5 };
var addToThis = function(a,b,c){
return this.num+a+b+c;
};
// console.log(addToThis.call(obj,1,2,3));
// functionname.call(obj,functionarguments);
var arr = [1,2,3];
console.log(addToThis.apply(obj,arr));
console.log(addToThis.apply(obj2,arr));
bind
var obj = { num:2};
var addToThis = function(a,b,c){
return this.num+a+b+c;
};
var arr = [1,2,3];
var bound = addToThis.bind(obj);
console.dir(bound);
console.log(bound(1,2,3));// 8
