es3 实现 map 和 bind

map

var map1 = function(a, fun) {
        var results = [];
        for (var i =0; i

bind

var bind1 = function(fun, obj) {
        return function(y) {
          return fun.apply(obj, arguments);
        }
      }
var fn = bind1(function(y) {return this.a + y}, {a: '1212----'})