call, apply, bind

 

A.call (B, x, y): in fact, can be seen as a function of A to B is placed in operation, x and y are the parameters A method.

function fn1(a,b){ 
   return a + b;
}

function fn2( ){ }


was val = fn1 (5.2 );
was VAL2 = fn1.call (fn2,5,2 );

console.log(val);//7
console.log(val2);//7

 

function fn1(){

    this.name = "zhangsan";
    this.myTxt = function (txt){
                  console.log("hello",txt);
                 };

}

function Person(){

    fn1.call(this);
}


where p = new Person ();
console.log(p.name);
p.myTxt("world");

 

"Chained" to borrow: