Function.prototype.bind函数兼容处理

今天敲代码的时候，想了想bind函数

Function.prototype.bind = Function.prototype.bind || function (target) {
  var self = this;
  return function (args) {
    if (!(args instanceof Array)) {
      args = [args];
    }
    self.apply(target, args);
  };
};

 

/*example 1*/ 
function f1(y, z){ return this.x + y + z;} 
//调用 1 
var g1 = f1.bind({x:1}, 2); //this.x = 1; y = 2; 
console.loog( g1(3) ); //this.x + y + 3 = 6; 
//调用 2 
var g2 = f1.bind({x:1}); //this.x = 1; 
console.log( g2(2,3) ); //this.x + 2 + 3 = 6 

/*example 2*/ 
var f2(x, y){ return x + y; } 
//调用 
var g3 = f2.bind(null, 1); //x = 1 
console.log( g3(2) ); //x + 2 = 3 

var eleBtn = document.getElementById("button") 
, eleText = document.getElementById("text"); 

eleBtn.onclick = function(color) { 
color = color || "#003399"; 
this.style.color = color; //此时的this指向eleText 
}.bind(eleText, "#cd0000");