模拟实现：

Function.prototype.call2 = function(context) {    context.fn = this;    var args = [];    for(var i = 1, len = arguments.length; i < len; i++) {        args.push('arguments[' + i + ']');    }    eval('context.fn(' + args +')');    delete context.fn;}// 测试一下var foo = {    value: 1};function bar(name, age) {    console.log(name)    console.log(age)    console.log(this.value);}bar.call2(foo, 'Cherry', 18);