var day=(new Date).getDay()===0;

//传统if语句

if (day) {

 alert('Today is Sunday!');

};

//运用逻辑与代替if

day&&alert('Today is Sunday!');

年月日 巧妙转化

https://segmentfault.com/q/1010000011341804

//对象深拷贝

var cloneObj = function(obj){

  var str, newobj = obj.constructor === Array ? [] : {};

  if(typeof obj !== 'object'){

  return;

  } else if(window.JSON){

  str = JSON.stringify(obj), //系列化对象

  newobj = JSON.parse(str); //还原

  } else {

  for(var i in obj){

  newobj[i] = typeof obj[i] === 'object' ? 

  cloneObj(obj[i]) : obj[i]; 

  }

  }

  return newobj;

};

数组拷贝

Array.prototype.slice.call(a)