function apply(fn,obj,args){
    //判断
    if(obj === undefined || obj === null){
        obj = globalThis
    }
    //为obj添加临时方法
    obj.temp = fn
    //执行函数
    let result = obj.temp(...args)
    //删除临时函数
    delete obj.temp
    //返回结果
    return result
}